What’s New in SharpCap 4.1

It’s been quite a long time now since SharpCap 4.0 was released back in June 2021. Throughout 2021 and part of 2022 we added some new features to updates of SharpCap 4.0. That works well for adding small features and tweaking things here and there, but to add some really substantial features needed a new version that could be worked on and tested without breaking SharpCap 4.0.

SharpCap 4.1 has been taken nearly a year in development to get it ready to release, although for at least six months there have been preview versions available to download and try. I have to express my thanks to everyone who took the time to try out new features and report their successes (and failures) to me to help improve the software.

Just looking for the SharpCap 4.1 download page? It’s here.

Major New Features

Live Stacking for Lunar/Solar/Planetary Imaging – see detailed solar system images live in SharpCap with no need to use separate applications for stacking and sharpening.

Lunar and Solar Mosaic Planner – automate capturing mosaics of the moon and sun.

Push-To Assistant – no GOTO mount? No problem! Use plate solving to quickly find a target with a Dobsonian or other manual telescope.

Remote Hardware Support – Support for hardware devices attached to another computer via ASCOM Remote/Alpaca

Hardware Reconnection Support – A glitched connection need no longer end your imaging run. SharpCap will attempt to reconnect to cameras and other hardware if they briefly disconnect.

Solar System Sequence Planner – automates the rapid capture of solar system videos, particularly when filter changes are required.

Other Changes

Live Stacking for Solar/Lunar/Planetary Imaging

Getting great images of solar system targets has always been a bit of a lengthy process – get everything set up, capture videos of the target, load those videos into a stacking application to select the best frames and stack, load the stacked image into some other application to sharpen it, then maybe photoshop for final adjustments. The results can be awesome, but they certainly aren’t immediate!

SharpCap’s new Solar/Lunar/Planetary live stacking feature changes all of that – you can filter for the best frames, stack, sharpen (two sorts, including wavelets) and enhance all live while observing. It’s great for outreach and showing friends and family the splendours of the planets. It will also help you improve your technique, since you will be able to try things out and see whether they improve the results pretty much straight away. Just set up as normal for your solar system imaging, get the camera running and the target in view and focused and select ‘Live Solar/Lunar/Planetary Stacking and Enhancement’ from the tools menu. Some sample results are shown below…

Saturn – typical raw frame
Saturn – 600 frames, sharpened and enhanced
Solar – typical raw frame
Solar – 200 frame stack, sharpened, colorized and enhanced

Live stacking of the planets is typically done at a fairly small ROI, so will work nicely even on relatively modest PCs or laptops. Solar or Lunar live stacking may require a powerful PC, particularly if you are using a high resolution camera.

There are a wide range of settings you can adjust to fine tune the stacking, including:

  • Number of frames to stack
  • Filtering to only include the best frames
  • Planet or surface alignment
  • Single or multi point stacking
  • Sharpening and noise reduction settings
  • Brightness, gamma, colour and saturation adjustments
  • Re-alignment of colour channels for colour images

You can even set the tool up to automatically capture a timelapse to video – great to record Jupiter’s rotation or watch the evolution of solar prominences.

Lunar/Solar Mosaic Planner

Capturing a whole disk Lunar or Solar image in a single shot requires either a short focal length (and therefore limited detail) or a camera with a very large -and expensive – sensor. The alternative is to capture a mosaic – taking multiple images of different parts of the disk and then stitching them together. Capturing a mosaic manually can be hard work, slow and there is always the risk of missing bits. Fortunately SharpCap 4.1 can help by automating the capture process.

All you need is a GOTO mount that SharpCap can control and a camera capable of taking videos.

In order to run a mosaic, SharpCap needs to know three things about the view of the target through the telescope :

  • The size of the lunar/solar disc in camera pixels
  • Any error in the GOTO mount co-ordinates in the vicinity of the target
  • The orientation of the camera view relative to the celestial (RA/Dec) directions

Fortunately, there’s no need to work these out for yourself – SharpCap has a selection of alignment procedures to help work these out quickly and easily.

For the Lunar mosaic option, there are three alignment modes available – Guided, Plate Solving and Manual. For a Solar mosaic, the only option is the Guided mode, since Plate Solving requires visible stars and Manual requires you to be able to set the orientation of the image in the camera – easy for a crescent moon, but hard for the sun!

Guided alignment is probably the best choice for most purposes – it involves choosing a side of the disc (lunar or solar) to align on as shown to the right, and then using the mount direction controls to line that point in the image up with 3 different points on screen selected by SharpCap.

The screenshot below shows the first stage of alignment with the top edge of the moon. The very top point on the moon – indicated by the yellow arrow – needs to be moved to the intersection of the red crosshairs by using the mount controls.

You need to repeat this procedure twice more – SharpCap will choose two more crosshair positions. Once completed, SharpCap can calculate all the information needed to run the mosaic (size of lunar disk, orientation, mount co-ordinate error).

Once alignment is complete, the next stage is to fine tune the mosaic settings to ensure you are going to get the results you want. The two key settings are the ‘Safety Margin’ – how wide an area around the target SharpCap will include in the capture area and the ‘Minimum Overlap’ – how wide the overlap between two adjacent panels has to be. SharpCap shows a diagram indicating the mosaic panels it intends to capture based on the current settings – this will update automatically as the settings are changed.

If you have an accurate mount with little backlash, you may be able to use small values for the safety margin and overlap, possibly reducing the number of panels that need to be captured. On the other hand, you may need to increase these values to deal with mount inaccuracy or backlash and avoid having any gaps in the mosaic.

The little pink cross? That shows where SharpCap thinks centre of the camera view currently is…

The final stage of setup is to set the camera settings to be used for capturing, how many frames to capture for each panel and a few other settings. This can easily be done by ticking a few boxes. SharpCap will even auto-set the exposure/gain on the predicted brightest panel of the mosaic and then use those settings for all panels.

All that’s left now is to press the ‘Run Mosaic’ button and sit back and watch it all happen. SharpCap will arrange for all the captured videos to be saved into a single folder for easy processing and show the current progress by highlighting the current panel in orange and completed panels in green. You can watch the actual mosaic capture in action below.

Once you have finished capturing, you can process using your normal stacking application, then stitch the panels together. The image below is a 9 panel solar mosaic captured using the SharpCap mosaic planner, stacked in PlanetarySystemStacker and stitched using Affinity Photo 2.

Push-To Assistant

Using a plate solving application (SharpCap supports Astap, Astrotortilla, Ansvr, ASPS, PlateSolve 2 and PlateSolve 3) revolutionizes finding a target using a GOTO mount. With plate solving, it doesn’t matter if the initial GOTO is off by a degree or so – one quick plate solve and recentre later and the target is right in the middle of the image.

But, what if you use a Dobsonian or a non-GOTO scope? Are you stuck with star hopping and hoping to spot a faint smudge to see the target?

SharpCap 4.1 adds a ‘PushTo’ assistant tool to help those who use non-GOTO scopes find their targets. Simply select it from the Tools menu then choose a target (either from the dropdown list of common targets or from the much larger full catalog). You can even type in co-ordinates if your target isn’t in SharpCap’s catalog…

Make sure that you can see stars clearly in the camera image and press the ‘Start’ button.

SharpCap will immediately start plate solving images from the camera. Once an image has solved successfully, SharpCap will show directions for how to move the telescope to get to the target and keep updating them as new images are plate solved and you gradually move towards the target co-ordinates. As you close in on the target, the required movement amounts will become smaller and the highlight colours will shade from reds towards yellows and then greens.

The use of colour helps you know what to do if you have to move away from the computer to adjust the telescope. Advanced users can connect both SharpCap and a planetarium application to a ‘virtual’ ASCOM telescope driver and have the planetarium application automatically update to the current plate solved position through the PushTo process.

Remote Hardware Support

SharpCap 4.1 supports using hardware (Cameras, Telescope Mounts, Focusers, Filter Wheels, Rotators and Switches) that are connected to a different PC via ASCOM Remote or ASCOM Alpaca.

If you have an ASCOM Remote server or an Alpaca server running on your network the SharpCap should automatically detect the devices that are being shared by the server. Shared cameras will appear in the ‘ASCOM Cameras’ section of the ‘Cameras’ menu, other shared hardware will appear in the appropriate dropdown in the SharpCap hardware settings page.

If you start your ASCOM Remote/Alpaca server after running SharpCap then the devices will not appear until you have selected ‘Rescan for remote hardware’ in the SharpCap File menu.

Hardware Reconnection Support

One of the things that SharpCap does while it is running is monitor for USB devices being connected to and disconnected from your system. One reason is so it knows when to refresh the list of available cameras, another is to detect when the camera in use has been disconnected and to close it down gracefully rather than having lots of errors pop up. To help keep track of any problems, each time a device connects or disconnects, SharpCap records that info in the SharpCap log.

We look at lots of SharpCap logs when trying to track down problems and one thing we noticed happening quite often was that a device (a camera, focuser, a filter wheel, etc) would disconnect from USB and then reconnect again maybe a second or two later. Maybe it happens because of a poor cable connection, or a glitch on the device itself, but if it is a device (particularly a camera) that you are using, it probably means a rude interruption to your imaging session.

To help deal with this, SharpCap can now automatically reconnect to most cameras and hardware if the connection drops out unexpectedly and then the device reconnects. For cameras, reconnection is supported for the following manufacturers/camera types: Altair, ZWO, QHY, Player One, SVBony and Webcams.

You can test this out for yourself if you have a supported camera – open the camera in SharpCap 4.1 and then pull out the USB cable from the camera. You should see a prompt like this pop up when SharpCap has detected the camera has gone missing

You can watch the time remaining count down if you want, but before it gets too low, plug the USB cable to the camera back in. SharpCap will detect the camera reconnect and show a prompt to indicate that it is trying to reconnect – like this.

After a few seconds the camera should complete the reconnect and SharpCap will carry on doing whatever it was doing before the disconnection, even in the middle of a capture or when running a sequence.

Automatic reconnection of ASCOM hardware (focusers, mounts, filter wheels, etc) works a bit differently. If SharpCap receives an error when trying to carry out an action on the hardware (moving the focuser, slewing the mount, etc), it will go through a series of retries to see if that fixes the problem in this order

  • If the ASCOM driver is unexpectedly disconnected, try to reconnect to it
  • Wait a short period (0.5s)
  • Retry the action
  • If still not working, disconnect and then try to reconnect the ASCOM driver
  • Retry the action again

If any of the retries is successful then SharpCap will continue as normal (apart from seeing a notification that a retry has happened). Hopefully this approach will help deal both with disconnection issues and also with cases where an ASCOM device glitches from time to time for some reason – with two retries it’s much less likely to become a showstopping issue.

Solar System Sequence Planner

SharpCap 4.0 introduced the incredibly flexible sequence editor along with the much easier to use Deep Sky Sequence Planner. Using the sequence editor to automate captures of solar system targets (for example capturing a target with a mono camera using multiple filters) was possible but complicated to set up.

SharpCap 4.1 adds a Solar System Sequence Planner, which makes it much easier to create sequences of that type from scratch.

As well as specifying a list of captures to run and the filters to use, you can ask SharpCap to auto set the exposure and gain for each capture (since different filters may require different settings). You can even set up different flat frames to be used for each filter in the ‘Flat Frames’ tab to take account of any blemishes on your filters that might otherwise leave dust shadows.

As with the Deep Sky Sequence Planner, individual steps can be tested on their own if it makes sense to do so and there is a ‘Test Run’ option that will run the whole sequence through with the number of captured frames set to a minimal value to check everything works. There’s also the ‘Advanced Edit’ button which will convert all the choices made in the planner into a sequence that can be edited further in the full sequence editor.

Goto Target Improvements

The first thing you might notice is a change of name from ‘Goto Co-ordinates’ in SharpCap 4.0 to ‘Goto Catalog Target/Co-ordinates’ in SharpCap 4.1 – that reflects the increased importance of using the catalog to pick a target rather than just entering co-ordinates.

Looking at the Goto window itself, you will also notice some changes :

  • There is an ‘Emergency Stop’ button that you can use to stop the GOTO if it looks like something is going wrong
  • The catalog selection option has moved above the co-ordinate entry option
  • When entering co-ordinates you can also add a target name
  • There are new options to use plate solving to refine the final position and also to reduce the exposure and increase gain during the procedure
  • If you use the Goto tool with live stacking running then it will save and finish your current stack before moving, and optionally start a new stack on the new target.

The default catalog has been enhanced with about 10000 extra HIP catalog stars (down to magnitude 7) as well as addition of some common names of stars and other targets that were missing. The solar system targets now also appear in the drop down ‘quick catalog’ list as well as in the full catalog.

Finally, if you use this tool (or the solar mosaic tool) to move the telescope to point towards the sun, SharpCap will now show you a warning about the dangers of viewing the sun through a telescope without the correct protective filters.

Camera Controls Improvements

SharpCap 4.1 brings some improvements to help you control your camera and easily get the settings that you need.

Exposure/Gain Shift Control

The first thing to notice is the new ‘Exposure/Gain Shift’ control that will appear at the bottom of the Camera Controls section for supported cameras :

Moving this control to the right will increase exposure but decrease gain, keeping the image brightness the same. Moving it to the left will do the opposite – decrease exposure and increase gain. It’s particularly useful for moving between deep sky imaging (long exposures, low gain) and focus/framing/plate solving (shorter exposures with higher gain). You can also use the F9 and F10 keys to adjust this control, with F9 halving exposure and increasing gain to match and F10 doing the opposite.

When you adjust either the exposure or gain control values manually then this control will reset to zero. This control will not appear for some cameras if SharpCap does not understand how setting the gain value of the camera affects image brightness. In particular, it will not appear for ASCOM cameras and for many QHY cameras.

Fine Exposure and Gain Adjustments

Another refinement is the addition of fine adjustment buttons to the exposure and gain controls, which can be seen to the right of the sliders for these controls in the screenshot below. These buttons make a change of about 2% to the value of the control each time they are pressed, so can be used for small changes if you find dragging the slider to an exact position tricky. Remember that you can also type in control values in the boxes that display the current value if you want an exact value and can make relatively large changes by clicking to the left and right of the current slider position.

Another thing worth noting in the image above is that the slider markers are in high contrast solid orange. This can make them easier to see, particularly if you are solar imaging and have sunlight falling on the computer screen. The high contrast sliders can be turned on in the ‘General’ page of the SharpCap settings.

Easy selection of ROI

A useful new feature also allows you to select a custom capture area by dragging around a selection rectangle on the current image. You can start this by pressing the ‘Select ROI’ button next to the ‘Capture Area’ drop down.

Pressing ‘Select ROI’ will make the red selection area box appear over the image, which you can move around in the normal way by dragging the corners, sides or who the whole box. Also, the ‘Select ROI’ button will change to ‘Apply ROI’. Once you have the area that you want inside the red selection rectangle, press the ‘Apply ROI’ button and the camera ROI will be changed automatically for you. Note that this feature is not available for some cameras that do not allow a ‘Custom’ ROI option.

Display Stretch Improvements

SharpCap 4.1 adds two new buttons to the display histogram stretch control to make it easier to use and more functional

  • An on/off button (top left) – using this you can turn the stretch off without adjusting the settings, then turn it back on again later
  • A locked auto stretch mode (bottom of the right hand column) – turning this on makes SharpCap re-apply the auto-stretch on a frame-by-frame basis – great for bringing out faint details under changeable conditions.

Live Stacking Improvements

Live Stacking gets some interesting improvements in SharpCap 4.1, covering stacking, image enhancement, interaction with guiding and mount movements and also usability.

Comet Mode Stacking

Comet Mode stacking can be enabled by ticking the ‘Align on a Comet’ box on the ‘Alignment’ tab. When comet mode is enabled, SharpCap will try to ignore all the stars in the image and attempt to locate the centre point of the brightest fuzzy blob in each frame. Frames will be stacked by lining up the fuzzy blob position from frame to frame, giving an image of the comet but allowing the stars to show as trails.

To get comet stacking mode working properly, it’s necessary to adjust the ‘Ignore stars filter size’ and ‘Detection Threshold’ values so that the comet is properly detected – turn on the ‘Highlight Detected Stars’ option and check that the box is drawn around the nucleus of the comet.

Remember to turn comet stacking off when you return to imaging normal deep sky targets!

Comet C/2022 E3 (ZTF) captured with SharpCap Comet Stacking, Jan 30, 2023

Image Enhancement Improvements

SharpCap 4.1 adds a new ‘Colour Noise Reduction’ option which is very effective at reducing the speckled colour noise visible when stretching the image – particularly in the early stages of a stack when noise levels are high. Colour noise reduction applies blurring to the hue and saturation data in the image, but does not affect the luminance, so tends not to blur image features.

Image sharpening has been refined, with the Weiner deconvolution now only applied to the luminance of colour images to avoid generating spurious colour noise effects. Unsharp mask sharpening can optionally be applied only to luminance.

Dithering and Recentring

The way that SharpCap interacts with a guiding application has been updated to help fix a number of issues that could crop up from time to time causing dithering frames to be considered for stacking. Additionally, there is now an option to periodically re-centre the stack using plate solving as an alternative to guiding and dithering.

The option to enable re-centring can be found on the right hand side of the ‘Guiding’ tab and is enabled when guiding is disabled or when ‘dither only guiding’ is active. You can specify the amount of image drift (in pixels) is allowed to accumulate before a recentre action is carried out. Of course, you must have a plate solving application set up on your PC and configured in SharpCap to use this option.

Usability Improvements

There are a couple of tweaks to make it easier to adjust the live stacking histogram and colour balance.

Firstly, it’s now possible to zoom the horizontal axis of the histogram by a factor of about 5 by ticking the ‘Zoom’ checkbox next to the ‘Log’ checkbox (the Log checkbox makes the horizontal axis logarithmic scaled, which is also good for getting fine adjustment near the black level).

It’s also now possible to make fine adjustments to the colour balance sliders by holding down the <SHIFT> key before you start dragging them with the mouse – when you do this the slider will move about 10 times slower than usual in response to the mouse movements.

Finally, there is a new ‘Stretch Mode’ option available to change the shape of the standard stretch curve slightly. Stretch Mode 2 corresponds to the default curve shape in older versions of SharpCap. Lower stretch modes apply more stretch in darker areas but may lead to brighter areas becoming blown out. Higher stretch modes may help with bright targets like M32 or M42 to help avoid the brightest regions being completely white.

Live Stacking Options

Finally, Live Stacking now has a small number of options that can be set in the settings tab, including:

  • Whether or not to auto-save the stack when the stack is reset or live stacking is closed
  • Whether a new stack should be started automatically when the current stack is cleared (if this is disabled then live stacking will enter pause mode when cleared – press ‘Start’ to begin a new stack)
  • Whether SharpCap should automatically disable the display stretch when live stacking is activated (and re-enable it when live stacking is closed). This can be useful because a display stretch that gives a good view of individual frames can over brighten a stacked image
  • Whether to create a log file containing information about each frame processed during stacking.

Image Processing Improvements

SharpCap 4.1 adds some new controls and options to the ‘Preprocessing’ section of the camera controls

  • A new flip control that can flip the image horizontally, vertically or both. This control should be used in preference to any flip controls provided by the camera itself, since it is applied after the image has been processed for dark subtraction and/or flat correction. Performing the flip after dark/flat correction means that there is no need to have dark and flat frames for each flip option that you intend to use – you can capture a single set of dark and flat frames and use those for all flip options.
  • An additional entry in the ‘Dark Subtraction’ control to enable ‘Hot and Cold Pixel Removal’. Like the ‘Hot Pixel Removal Only’ option, this does not actually use a dark frame – it simply and automatically eliminates hot and cold pixels by looking for pixels that have values that are wildly different to neighbouring pixels.
  • Background subtraction has two new non-linear background removal modes which may help in cases where there is a complex gradient in light pollution.
  • A new option to mask overexposed pixels to black, which may be useful when imaging the chromosphere of the sun to automatically set the over-exposed solar disk to black.

Hardware Improvements

SharpCap 4.1 adds an incredibly convenient new toolbar button to connect all hardware – focusers, mounts, filter wheels, etc. You’ll find it on the very right hand side of the toolbar, looking like a blue plug (US style) on a short lead. When it is highlighted (as shown to the right), all hardware is already connected and pressing it will disconnect. When not highlighted, pressing it will connect all selected hardware.

Another thing to watch out for is the addition of ASCOM Switch support – this lets you control ASCOM switch devices from within SharpCap, meaning that you can adjust things like dew heaters and 12V power outputs without leaving the application. Additionally, if your switch device provides any info readings, you’ll see those in SharpCap too.

If you have updated from an old version of SharpCap 4.0 then ASCOM Rotator support might be new to you too. You can adjust the orientation of your rotator from within SharpCap and use SharpCap to match orientations with an existing image by using the ‘Goto Image’ tool.

Finally, if you are using a mount or focuser in SharpCap, you can now set a ‘settle time’ to adjust how long SharpCap should wait after the device reports that it has stopped moving before trusting the setup to actually be steady. This can be adjusted in the Hardware settings

Camera Support Improvements

SharpCap 4.1 adds some important features and updates for various types of cameras

  • Atik Cameras – Filter wheel support added along with adding support for controlling gain on older cameras
  • Basler Cameras – Update to support Pylon 7.3.0
  • Moravian Cameras – Add filter wheel and GPS module support
  • Player One Cameras – Add cooled cameras support

Additionally there have been many small improvements and bug fixes across the whole range of cameras supported by SharpCap.

Please note that SharpCap 4.1 does not include support for iNova Cameras. iNova appear to have left the camera market and never provided code to access their cameras from a 64-bit version of SharpCap (which is now the recommended and default version for SharpCap 4.1).

Focus Scores/Autofocusing

SharpCap 4.1 includes improvements to focus detection and autofocusing algorithms, including:

  • Option to make the selection area track the brightest object in the image for planetary style focus scores
  • Option to use 2×2 binning or to select a colour channel for some focus score types
  • Better detection of ‘donut’ stars – created by out-of-focus SCT or Newtonian telescopes when using multi-star FWHM
  • Improved detection of best focus curves
  • An experimental option to use a ‘V’ shaped curve fit rather than the default ‘U’ shaped fit.
  • Autofocus sequencer steps will return to the original position if they fail to find best focus, allowing for retry or continuing at previous focus position
  • Smart Scanning ‘backward jump’ to try to fill in missing data at the start of the scan removed for now due to causing more issues than it solved.

Hotkeys

While most people use a mouse, trackball or touchpad to control SharpCap, experienced users often find that using keyboard shortcuts for some features is faster and more accurate. SharpCap 4.1 adds a selection of new keyboard shortcuts, including

  • F9 and F10 adjust the Exposure/Gain shift control.
  • The current image zoom level can be adjusted using CTRL+PLUS and CTRL+MINUS to zoom in and out.
  • CTRL+1 sets 100% zoom, CTRL+0 zooms to fit the image in the available on-screen space.
  • CTRL+SHIFT+F1 to F12 change filter if a filter wheel is connected
  • CTRL+SHIFT+C – toggle connect/disconnect of all hardware (filter wheel, mount, focuser, etc)
  • CTRL+SHIFT+G – launch GOTO catalog target window
  • CTRL+SHIFT+H – activate histogram
  • CTRL+SHIFT+L – activate Live Stacking
  • CTRL+SHIFT+P – activate Polar Alignment
  • CTRL+SHIFT+A – activate deep sky image annotation
  • CTRL+SHIFT+R – run an automatic refocus
  • CTRL+SHIFT+V – activate pixel value readout

Finally, it’s worth knowing that the ESCAPE key will stop the current capture, and if held down it will cancel a simple sequence of captures started from the ‘Start Capture’ window.

New Sequencer Steps

SharpCap 4.1 adds a range of new sequencer steps which can be used in the sequence editor, as well as being used by tools such as the Solar System Sequence Planner and the Mosaic Planners. The new steps include :

  • A step that will wait for the next frame to arrive from a camera running in live view (‘Wait for next live view frame’)
  • A ‘Repeat until time’ step that will repeat the sub-steps until the specified time of day
  • A ‘Wait until later than’ step which will complete when the current time is later than the specified time
  • A step to save settings to a capture profile (‘Save Camera settings to profile’)
  • A step to put all capture files from the sequence in a single folder (‘Arrange captured files in a single folder’)
  • Steps related to connecting, disconnecting or adjusting ASCOM switch devices.
  • Steps to auto set exposure and gain for solar system targets or for flat frame capture (‘Solar system auto set exposure/gain’, ‘Flat frame auto set exposure/gain’).
  • A step to adjust exposure/gain for plate solving and focus by reducing exposure and increasing gain (‘Set exposure/gain for plate solving and focus …’). Will adjust settings back to original once the sub-steps have completed
  • Steps to allow GOTO solar system targets with optional offsets to support mosaic captures.

Other Improvements

Polar Alignment GOTO based rotation

If you have SharpCap connected to a GOTO mount then a new set of buttons will appear in the Polar alignment tool so that you can perform the rotation using the GOTO mount. Hold down either the ‘Rotate East’ or ‘Rotate West’ buttons to move the mount in RA, and let go when it has moved far enough

Disk Space Monitoring

SharpCap now monitors the free space on the disk which capture files are saved to, and displays the current figures in the status bar, as shown below.

Additionally, SharpCap will show warning notifications when the amount of free disk space drops below 1Gb, then 100Mb, then a critical warning when it drops below 10Mb.

Simpler Installation

Previous versions of SharpCap sometimes needed to download and install a Microsoft component called the ‘.NET framework’ from the internet. If this wasn’t already installed and you had no internet connection then the SharpCap installation could fail. SharpCap 4.1 is a self-contained installer and does not need a separate ‘.NET Framework’ installation, so this issue is avoided.

Additionally, SharpCap 4.1 will help you install a SharpCap Pro license key by detecting automatically that there is a license key on the clipboard when the program starts or when you show the ‘SharpCap Pro License’ window. If a key is found on the clipboard then you are prompted to use that as the new key.

SharpCap Pro – Pricing Update

Believe it or not, it’s been over 4 years since the introduction of SharpCap Pro back in April 2017. Back then we set up the SharpCap Pro licensing system with goals of affordability and fairness. In particular, we aimed to

  • Keep the basic features free – simply working with a camera and capturing images or videos does not require a SharpCap Pro license and never will.
  • Allow try-before-you-buy – you can try out almost all SharpCap Pro features before you buy a license to ensure that they work for you and so you can decide if the license is worthwile. Of course there are restrictions on what you can do when you try out without a license – mostly if you try a Pro feature you can see the results on screen but cannot save any images or videos until you restart SharpCap.
  • Keep the price affordable – by opting for a subscription model rather than a one-time purchase, the price you pay to buy a SharpCap Pro license can be kept low. Of course we hope that you will love SharpCap Pro and renew your license year after year*, but if for some reason you don’t, you haven’t spent a fortune on software that you don’t use.

Of course, things were different back in 2017…

  • There were only five Pro features in SharpCap 3.0 – Dark Correction, Flat Subtraction, Semi-automatic focus assistance, Polar Alignment and Python Scripting. With the introduction of SharpCap 4.0, there are now over 20 key SharpCap Pro features, including Sequencing, Background Subtraction, Banding Suppression, Advanced Live stacking features, Smart Histogram, Seeing Monitor and more…
  • SharpCap was still a part-time project back in 2017. Now, since the start of 2021, it’s my full time job. This has allowed much improved progress to be made on SharpCap 4.0 and improving the quality of the software, but it does mean that SharpCap Pro license sales have to be enough to pay all the household bills for this to continue.

The result of all these changes is that the time has come at last for the price of a SharpCap Pro license to increase. The price for a 1 year SharpCap Pro license will rise from £10 to £12 when SharpCap 4.0 is fully released. This is expected to happen on or just after 1st July 2021. Prices in other currencies will also rise by a similar amount, although we have also taken account of changes in exchange rates and trying to make the price a reasonably sensible ’round number’.

We hope that you will agree that SharpCap Pro licenses are still great value for money – a year’s access to SharpCap Pro for considerably less than the average cost of a thread adaptor ring or extension tube!

*We know that some of you aren’t entirely happy with the subscription payment model – we’re hoping to be able to re-introduce the ability to purchase permanent licenses later this year.

What’s New in SharpCap 4.0

SharpCap 4.0 has a whole host of new features, but there are three major features that give SharpCap far more power and flexibility than ever before:

additionally there are a number of ease-of-use improvements designed to make your imaging easier and less error-prone:

Still Camera Mode

SharpCap up to version 3.2 has run every camera like a video camera – that means that the camera is constantly taking images which show in SharpCap’s display. If you choose, you can save those images to video or picture files, but you cannot stop the camera from capturing images.

SharpCap 4.0 introduces Still Camera Mode as an alternative to the default Live Video Mode. In still camera mode, SharpCap only takes images when requested by the user pressing one of the capture buttons or by some other SharpCap function requiring an image to be captured. Most of the popular brands of camera supported by SharpCap can be used in Still Camera Mode, including Altair, QHY, SVBony, ZWO and ASCOM cameras.

You can switch between Live Video Mode and Still Camera Mode by using the new Live View button in the toolbar. When the button is highlighted you are in video mode, when it is not highlighted you are in still camera mode.

In Live Video Mode, the Live View button is highlighted, the image will constantly update and the familiar Start Capture, Quick Capture & Snapshot buttons are available.
In Still Camera Mode, the Live View button is not highlighted, the camera only takes images on demand and a new Framing Shot button is visible – this allows you to capture an image without saving it for purposes such as focusing, setting exposure, framing the image, etc.

Still Camera Mode is best suited to deep sky imaging, and is particularly useful for use with cameras that have a physical shutter (for instance DSLR cameras) or large format CCD cameras that take a long time to download the image to the computer. Still Camera Mode is also used by the Deep Sky Sequence Planner to ensure consistent results and allow reliable dithering.

Read more about still camera mode here.

The Deep Sky Sequence Planner

The Deep Sky Sequence Planner brings easy-to-use automated imaging to SharpCap for the first time. By simply choosing a few options regarding the set-up of your imaging session and entering a list of the types and numbers of frames to capture, you can quickly build an automated imaging plan. What’s more, almost every part of the plan has an individual Test button that you can use to make sure that the individual steps work correctly before letting the whole plan run.

Some of the things that the sequence planner can automate include:

  • Setting appropriate camera settings, including measuring sky brightness and using the Smart Histogram Brain calculations.
  • Using a GOTO mount to slew to the target and optionally center it using plate solving
  • Control camera cool down and warm up
  • Monitor autoguiding and dither between frames if desired
  • Autofocus before imaging and or when changing filters

Once you have designed your imaging sequence, you can even perform a Test Run to check that everything works when the individual steps are put together – this will run all the separate steps in the sequence but only capture a single frame of each type. You can then run your imaging sequence for real – either returning to the warmth of the house or monitoring SharpCap’s progress via the Sequence Progress Window.

Note: The Deep Sky Sequence Planner is a SharpCap Pro feature. Without a SharpCap Pro license, sequences will only be allowed to run for a maximum of 5 minutes.

Read more about the Deep Sky Sequence Planner here.

The Advanced Sequence Editor

The Deep Sky Sequence Planner uses a much more powerful and flexible sequencing technology built into SharpCap 4.0 to help plan and execute its sequences. If you want to set up an automated imaging sequence that isn’t possible using the Deep Sky Planner, you can use the full Sequence Editor to achieve your goals. You can even start out designing a sequence in the Deep Sky Sequence Planner and then press the Advanced Edit button to switch to the advanced editor to modify your sequence further.

The SharpCap Sequence Editor

Sequences are built by combining in various combinations and orders in excess of 90 basic steps, each of which carry out a simple function such as setting the camera exposure, capturing frames or operating a mount or filter wheel.

Steps can be dragged from the Available Steps area on the left into the Sequence List in the centre, gradually building up a list of tasks for SharpCap to carry out. Things you can do from the sequencer include:

  • Selecting cameras, controlling their settings and capturing still frames or videos
  • Controlling filter wheels and GOTO mounts
  • Controlling electronic focusers, including autofocusing
  • Monitoring guiding applications, triggering dithering
  • Repeating groups of steps a fixed number of times or until a certain time
  • Waiting until a certain time or until an event such as sunset
  • Running other programs or launching SharpCap Python scripts

As with the Deep Sky Sequence Planner, the Sequence Editor has a strong focus on being able to test your sequences as you build them – use the Test button frequently to check that individual steps are correctly configured and work as expected.

The possibilities are already almost endless, and new functionality will be added via additional available steps to make the SharpCap sequencer even more powerful in future.

Note: The Advanced Sequence Editor is a SharpCap Pro feature. Without a SharpCap Pro license, sequences will only be allowed to run for a maximum of 5 minutes and certain steps are disabled entirely.

Read more about the Sequence Editor here.

Additional Image Processing Options

SharpCap 4.0 adds new built in image processing options:

  • Background Subtraction – this will remove a constant background brightness from deep sky images, which is particularly useful for eliminating sky glow (light pollution). The subtraction is compatible with dark and flat frame correction and will deal with situations where the sky glow has a colour cast.
  • Planetary Stabilization – this option keeps a planet (or other bright disc) in the center of the camera frame by offsetting each image as required. While it won’t help if the planet starts to drift out of view entirely, it will keep the target steady, helping with focus judgements and with outreach presentations.
  • Banding Suppression – some CMOS cameras have a tendency to produce fine horizontal bands that are visible when dark images are stretched to display faint deep sky targets. SharpCap can apply a targeted smoothing function to the image that will only affect these fine horizontal lines in the darkest parts of the image, reducing the effect of this banding on image quality.
These images show CMOS image banding without banding suppression (left) and with banding suppression (right).

These image processing options will not only affect the image seen on screen in SharpCap, they will also be applied to image data saved to video or image file (except for raw unprocessed frames saved while live stacking). Background Subtraction and Banding Suppression can be used in conjuction with Live Stacking.

Read more about Background Subtraction, Banding Suppression and Planetary Stabilization.

Pixel Value Readout

The pixel value readout overlay for a colour camera in RAW16 mode

Sometimes you want to see more detail about the brightness of the image than the histogram can provide – to see the intensitity of individual pixels. The Pixel Value Readout tool gives you that detailed information. Simply select the tool from the menu and then click on the area of interest in the image to see an overlay showing the data for the selected pixel.

You can use the zoom functionality to zoom in until individual pixels are clearly visible to be sure of selecting the target pixel.

For a colour camera in RAW mode, the overlay shows not only the red, green and blue values that the pixel has after debayering, but also the raw value of the pixel and which colour in the bayer matrix it is.

Read more about Pixel Value Readout.

Pixel Position Readout / Click to Recenter

Getting your target framed just right when you are deep sky imaging can be a bit of a process of trial-and-error. Even if you use plate solving to try to correct for any GOTO errors, adjusting framing if the target needs to be slightly off-centre is tricky.

With SharpCap 4.0, a GOTO mount and a configured plate solving application, all this becomes easy. Select the Pixel Position Readout / Click to Recenter tool, perform a plate solving operation if you haven’t already and SharpCap will then be able to show you the co-ordinates of any pixel in the image, along with the direction of the +/- RA & Dec axes within the image.

Double click on any point in the image and SharpCap will calculate the correct commands to send to your GOTO mount to put that point in the center of the image – even taking acount of any offset due to inaccurate mount movements.

The click-to-recenter part of this feature requires a SharpCap Pro license.

Read more about Pixel Position Readout / Click to Recenter.

Atmospheric Dispersion Corrector (ADC) Alignment

An atmospheric dispersion corrector is an invaluable tool for planetary imaging when the target planet is at a relatively low altitude in the sky – it allows you to largely cancel out the colour channel offset in the image created by atmospheric refraction.

Adjusting an ADC can be a bit of a fiddly procedure, largely because judging the point where best correction is achieved can be hard (just like judging the point of best focus can be hard). SharpCap’s ADC alignment tool helps out here but calculating the offset between the different colour channels in the image and showing an exaggerated representation of that overlaid on the image itself.

As well as showing the current colour channel offsets on the image, you will see a graph showing how the colour channel offsets have changed recently – allowing you to track the effects of your adjustments to the ADC.

Read more about ADC Alignment.

Improved ASCOM Hardware integration

SharpCap 4.0 has some significant improvements in the way that it integrates with ASCOM hardware such as GOTO mounts, focusers and filter wheels.

  • The ability to flip the direction that a GOTO mount moves in response to the up/down or left/right movement buttons.
  • The ability to adjust focus automatically when the filter is changed if your ASCOM filter wheel supports the Focus Offset feature and you have configured focus offsets.
  • The ability to compensate for backlash in ASCOM focuser movements. You can either configure the amount of backlash in SharpCap or tell SharpCap that the ASCOM driver is itself compensating for backlash.

All of these features can be configured in SharpCap’s Hardware Settings.

What’s New in SharpCap 3.2?

SharpCap 3.2 has a strong focus on improvements to the functionality available when Live Stacking – there are improvements and additions to other parts of the application, but most exciting new features are related to Live Stacking…

So, without further introduction, a quick tour of the new and improved features in SharpCap 3.2

New Night Mode Colour Scheme

SharpCap has had a basic night mode option for a long time, but even I’d have to admit that it wasn’t really very effective – it sort of made the controls and window dimmer and red, but that was about it. SharpCap 3.2 brings a new night mode colour scheme that is designed to give low monitor brightness but retain good readability. The use of an orange colour for text and controls instead of the more traditional red makes text legibility much better without adding significantly to the screen brightness. You can now toggle in/out of night mode quickly using the ‘F12’ key.

You may notice that a couple of things are not changed into a dark colour scheme – in particular scrollbars and the window title bar. It turns out that changing the colour these iterms isn’t possible without an awful lot of work, so these are currently not switched into night mode.

Two Monitor View

This has been quite a popular user request – the ability to show all the controls on one monitor and show just the captured image on a second monitor. This can be toggled using the keyboard (CTRL+F12) or using the new ‘Two Monitor View’ button on the toolbar.

As you can see below, two monitor view is particularly helpful in Live Stacking mode because it allows room for the various Live Stack control and information tabs to be split up so that more than one is visible at a time.

Two Monitor View will be a SharpCap Pro feature.

Folder Monitor Virtual Camera

SharpCap can talk to a wide range of cameras directly and even more via either an ASCOM or DirectShow driver. It also has a pair of testing (simulated) cameras that can be used to try out the features of the program on cloudy nights. The Folder Monitor Virtual Camera adds another way to get images into SharpCap – it can read existing or newly added image files from a directory opening up new ways to use SharpCap. As a couple of examples:

  • You have a camera that isn’t supported by SharpCap, even using a DirectShow or ASCOM driver, but you have an application that will capture frames from that camera and save them to a folder. You can use the folder monitor virtual camera to load each new frame saved to the folder into SharpCap, allowing you to access SharpCap tools like focus measurements, live stacking, etc.
  • You have a series of image frames of a target captured with either SharpCap or another capture application. You can use the folder monitor virtual camera to live stack these frames in SharpCap (or repeat the live stacking with different parameters if these were frames originally saved in SharpCap).

The folder monitor virtual camera only has a limited set of controls available – it’s obviously not possible to adjust camera controls like exposure, gain or colour balance when the images are being read from saved files! The resolution and colour space values are also determined by the contents of the image files being loaded and cannot be changed.

You do have the ability to browse for the folder that contains the files you want to work with and move through the list of files in the folder either automatically (in play mode) or stepping forward/back manually in pause mode. Additionally dark subtraction and flat frame correction can be applied and the frame rate limit can be set.

To select the folder source, press the ‘Browse’ button and either select a folder (which will process all image files in that folder) or select an image file (PNG, TIF, FITS and JPG supported), which will process all image files of that type in the same folder.

Image files are always processed in date order (starting with the oldest first). The resolution and colour space values are selected from the first frame processed, and files that have different resolutions or colour space settings will be skipped. If SharpCap runs out of files in the folder (or if there are no image files in the folder initially) then it will wait for new image files to be added and load them when they appear.

The Folder Monitor Virtual Camera is a SharpCap Pro feature.

Live Stacking Improvements

Many EAA (Electronically Assisted Astronomy) enthusiasts are now keen to run their entire imaging session within a live stacking tool such as SharpCap – they are also often keen to avoid any post-processing in other applications. A number of changes in this version of SharpCap support this sort of EAA use.

Noise Reduction and Sharpening

The Live Stacking enhancement tab now contains options for applying noise reduction and/or sharpening to the stacked image each time it is updated by adding a new frame.

There are two noise reduction and two sharpening options available (as well as the default of ‘off’ for both!). The Gaussian Blur noise reduction and Unsharp Mask sharpening are basic tools which you would find in most image manipulation applications. They are relatively quick to calculate. The downside of these options is that use of the ‘Gaussian Blur’ noise reduction tool will tend to reduce image sharpness and the ‘Unsharp Mask’ sharpening tool will tend to increase image noise. With careful adjustment of the parameters, these simple tools can suffice to give useful image improvements in many cases. The Gaussian Blur noise reduction tool does not require a SharpCap Pro license to use.

SharpCap Pro users also have the option to use the more sophisticated tools:

Bilateral Filter noise reduction which can lower noise with less blurring effect than the Gaussian Blur option. This tool will tend to remove noise within areas of similar colour without blurring an area of one colour into an adjacent area of another colour. The radius option selects over how large an area (in pixels) the smoothing is effective while the luminance tolerance specifies how different colours have to be for the algorithm to try to preserve the differences between them. Setting the luminance tolerance too high will make this algorithm give results similar to the gaussian blur option

Weiner Deconvolution is an advanced image sharpening algorithm that uses an estimate of the PSF (point spread function) of the image to try to correct for blurring introduced by optics, seeing and stacking. The estimate of the PSF is calculated from the shapes of detected stars in the stacked image (so this sharpening feature will only work for images containing stars). The only control that needs adjusting for this algorithm is the Signal-to-Noise ratio slider, which helps the algorithm determine which parts of the image are noise (and therefore shouldn’t be sharpened) and which parts are useful image (and should be sharpened). If this slider is turned up too high then you will see artifacts in the image – typically dark rings around stars and an ‘orange skin’ look to faint areas – if these symptoms are seen then turn down the S/N Ratio slider until a good result is achieved.

Note that both of the advanced algorithms require more computation than the simple ones, so using a fast PC is advisable, particularly for high resolution cameras.

Saturation control

This is a simple addition to the live stacking colour balance controls that allows the saturation to be adjusted in the range 0 (monochrome) -> 1(normal colour) -> 3 (highly enhanced saturation). Like the white balance controls, saturation adjustment is a SharpCap Pro feature.

PHD2 Guiding and Dithering support

While SharpCap live stacking can automatically correct for image drift and rotation on unguided (and even Alt/Az) mounts, fixed pattern noise in the images being stacked can contribute to visible artifacts in the stacked image. A common example of this problem is so called ‘raining noise’ where darker or brighter pixels create dark or light streaks across parts of the image as their position on the stack drifts gradually. The resulting pattern can look like rain slashing downwards, hence the name. While proper use of darks and flats can help reduce or eliminate this issue, in some cases dithering can be the best approach as the random movements of the darker/lighter pixels ensure that there is no visible pattern that is easily noticeable to the eye.

SharpCap 3.2 adds support for monitoring the status of the PHD2 guiding application and also automatically triggering the dither functionality of PHD2 at a selectable interval. When the dither interval timer expires, SharpCap will wait for the current frame to end, stack it, pause live stacking and send a message to PHD2 to begin the dither movement. Once PHD2 reports that the dither movement has settled, SharpCap will wait for the frame currently in progress to end and then unpause live stacking and start the dither timer running again. This sequence should ensure that any frames that are streaked by the dither movement are not included in the stack.

Additionally it is now possible to set up SharpCap to automatically stop stacking if PHD2 loses it’s guiding lock and/or refuse to start stacking if PHD2 is not guiding – the first option is helpful to prevent a stack from being spoilt if guiding fails and the second simply helps avoid mistakes if you always want to guide while stacking.

Monitoring the status of PHD2 and automatically stopping stacking if PHD2 stops guiding does not require a SharpCap Pro license, but the automatic dithering function does. Note that currently the only guiding application supported is PHD2 and it must be running on the same PC as SharpCap.

Option to save exactly as seen on screen

The display stretch controls in the mini histogram on the right hand side do not affect the saved image (they are only designed to affect the image as shown on screen in SharpCap). However, if you did want to save the image exactly as seen on screen the only way to do it was to take a screenshot, which is hardly idea.

SharpCap 3.2 adds the option to save the image exactly as seen onscreen. The saved image is always saved as a PNG file in 8 bit depth regardless of camera bit depth or other save settings, since the goal here is to save an image for later vieweing rather than further processing. To avoid confusion with the normal save functionality, the save as seen function is activated by a small save button in the mini histogram.

Additionally, for convenience while live stacking the functionality can also be accessed from the live stack save drop down button.

Expanded Live Stack controls in two monitor mode

Perhaps a picture can say it all – when in two monitor mode you have much more space available so the Live Stacking controls use it

Auto “Stack Save and Reset” option

This is a simple but handy addition Live Stacking which allows you to set up the software to automatically save the current stack and reset to start stacking again automatically after a user defineable total stacking time has been reached. By setting this to 5 minutes, at the end of an hours stacking you will have 12 completed 5 minute stacks saved which can then be further post-processed in a more traditionally stacking application. The use of a number of shorter stacks reduces the chance of a large amount of data being spoiled by an unlucky event such as a airplane trail or by changing conditions. Of course live stacking has other ways to control these problems (Sigma clipped stacking, FWHM filter, brightness filter, etc, so be sure to explore those features too).

Other Improvements

Filename template improvements

The following new tags have been added to the filename templating engine

  • FrameDate
  • Exposure
  • Gain
  • BlackLevel

The Exposure tag will format the exposure in either seconds or milliseconds. The Gain and BlackLevel values are only available when the exposure time is over 100ms.

Flat frame capture improvements

SharpCap 3.2 improves the built in flat frame capture tool by allowing you to correct for camera black level (dark correction) when capturing flat frames. There are two ways that you can do this

  1. Use a pre-captured dark frame that was captured at the same camera settings that you are planning to use to capture flat frames. This provides the best correction, but requires you to manually capture and select a dark frame with appropriate settings. You should use this option if your flat frame exposure time is long enough to give you problems with hot pixels.
  2. Check the ‘Capture and Subtract bias frames to remove offset’ option in the Capture Flat window (this option can only be selected if normal SharpCap dark subtraction is *not* enabled). With this setting enabled, SharpCap will capture normal flat frames and then capture a series of very short exposure bias frames which allow the camera black level to be corrected for.

When using the automatic bias frame capture and subtraction you don’t need to cover the telescope aperture while the bias frames are being captured – the reduction in exposure time will be enough to make them dark (or close to dark) and even if they are not entirely dark it will not have an adverse impact on the quality of the final flat frame.

Website Update

Hope that you like the new-look website. Almost all of the content from the old website has been brought accross with corrections and improvements along the way. The new site is cleaner and more modern looking and navigation and usability on mobile devices have been improved.

If you find any big problems, please let me know via the SharpCap forums.

What’s New in SharpCap 3.1

With SharpCap 3.1 now ready for release, here’s a quick rundown of the new features and improvements that have been added.

Mini Histogram

Something I probably should have added long ago – an always on mini histogram in the control panel that’s integrated with an easy-to-use way of stretching the image for display to bring out the fainter details…

This doesn’t have all the power of the main histogram – for instance it only updates a couple of times per second to conserve resources and it doesn’t support the selection area option, so it always shows the histogram of the entire frame, but it makes up for that by always being available.

As well as being able to inspect the image histogram, you can tweak the display stretch function by dragging the three dashed vertical lines that indicate the black point, mid point and white point. These adjustments make it very easy to pull out faint detail on the screen (they don’t affect data being saved to file). You can also use the auto stretch button (the lightning bolt) to have SharpCap automatically stretch the image for you and also reset the stretch back to default using the reset button. To round things off, the intensity of the auto stretch is configurable in the SharpCap settings, so you can pick an auto-stretch intensity that works for you.

Note that the mini histogram does not require a SharpCap Pro license, but the use of the auto stretch button does.

Auto Restore of Camera Settings

SharpCap 3.1 automatically saves camera settings when you close a camera and then restores them the next time you open that camera. This behavious is enabled by default, but if you prefer to return to the old way of working, the auto-restore can be disabled in ‘general’ tab of the SharpCap settings.

If you need to stop the settings from being restored on a particular occasion, but don’t want to turn this feature off completely, then simply hold down <CTRL> while opening the camera to disable settings restore temporarily.

Smart Histogram

Ever wondered whether you are using the right gain or exposure when deep sky imaging? Whether 6x ten minute exposures really do give you more detail than 12x five minute exposures? No more guesswork required with the new SharpCap Pro Smart Histogram feature. In combination with the results of Sensor Analysis (see below), SharpCap can measure the sky background brightness for you and then perform a mathematical simulation of the impact on final stacked image quality of using different gain and exposure combinations. You can also see graphs showing the impact of using longer or shorter exposures (or lower or higher gain) than suggested.

If you try this using a modern, low noise, CMOS sensor you might be pleasantly surprised to find out that the optimal exposure length isn’t nearly as long as you imagine and that maybe the complexities of guiding will become a thing of the past (The use of long – 5 to 10 minute or even longer – exposures in traditional deep sky imaging is not required to see faint targets, it’s actually required to deal with the high typical read noise of CCD sensors. Since the optimal exposure length is proportional to the square of the read noise and CMOS read noises can be 1-3 electrons instead of 8-10, exposures can often be much shorter with no loss of quality).

The basic form of Smart Histogram takes the form of a pair of coloured bars along the top of the histogram area :

The top bar with the red, amber and green sections shows the impact of your camera’s read noise on the total image noise at that brightness level. For areas of the image in the red highlighted region of the histogram, the camera read noise dominates the total noise (>50% of total noise). In the amber region, the read noise contributes significantly to the total noise (10% to 50%). In the green region, the contribution from read noise is small (<10%). The size of the red and orange zones will vary as you vary the gain and offset controls of your camera. Once you have picked values for those controls, you should adjust the exposure so that the histogram peak corresponding to the sky background is just to the right of the orange zone – this will give you optimum image quality without entering the zone where increased exposure time has diminishing (to zero) returns.The lower bar indicates the effect of bit depth on the quality of captured image. In high bit depth modes (12, 14, 16 bit), the bar is green and light green – the light green section shows the range where the increased bit depth is not helping you because the total pixel noise equals or exceeds the distance between ADU levels in 8 bit mode. In the light green region, the use of high bit depth simply means that you are recording the pixel noise in greater detail!

In 8 bit modes, the lower bar is amber and green :

The amber region indicates the part of the histogram where you are throwing away data by using 8 bit mode (ie you would get more image quality by switching to 12/14/16 bits for parts of the image in this histogram region). The amber region will shrink to the left as you increase the camera gain level, and at the high gains used in planetary imaging it may not be visible at all – this shows why there is no need to use high bit depth modes for planetary ‘lucky’ imaging (and also that the Smart Histogram isn’t only useful for deep sky!).

The coloured bars at the top of the histogram are just the ‘quick’ way to use the Smart Histogram features, giving you some basic guidance on exposure times and bit depths. For a more in-depth calculation that gives recommendations on gain, offset, exposure and bit depth, press the ‘Brain’ button next to the coloured bars to bring up the Brain window.

The ‘Brain’ window is quite complicated, but if you follow it from top to bottom it should not be too hard to use.

The goal of the Brain is to help you pick the right camera settings to get the best deep sky images. Note that the Brain is *not* aiming to give you fabulous quality sub-exposure images, it is calculating how to get the best final image when you stack all frames taken in a set period of time (1 hour by default). The calculations will work out for you whether it is better to take 360 x 10 second images or 10 x 360 second images or some other combination.

The first step is to measure (or enter) your sky brightness – this is measured in electrons per pixel per second and is a measure of how much signal is arriving at every pixel on your camera every second from sources that we don’t really want – light pollution and thermal noise being the main culprits. If you press the ‘Measure’ button then SharpCap will set the gain to maximum and take a number of increasing length exposures to measure this value – you should point the telescope at an area of sky without nebulosity or many stars to get a good measurement.

The next step is to set limits and targets for the calculation – you can set a minimum and maximum exposure to consider (typically maximum exposure is determined by mount tracking/guiding quality and minimum by how much data you have to save with very short frames or stacking speed for live stacking). You can also set the time you intend to image for (not critical, changing this will *not* change the suggested values) and the contribution you are prepared to tolerate from the sensor read noise in the final image noise level. If you select a ‘Read Noise Limit’ of 10%, that means that the calculations will allow the total noise level in the final stacked image to increase by 10% above the minimum achievable noise level (ie to go from 10 to 11 on some scale).

The last choice in this section determines how the gain is chosen – the two options are ‘Unity Gain’ which aims for 1 electron per ADU (or as close as possible) and ‘Max Dynamic Range’. ‘Max Dynamic Range’ finds the gain where the final stacked image will have the maximum ratio between the brightest thing that is not quite saturated and the noise level. Max Dynamic Range will often (but not always) choose the minimum gain value.

Once the sky background is measured and the limits and targets are set you can examine the results. In the image above, you can see that with a 5e/pixel/s sky brightness (quite bad light pollution), the calculation is recommending a gain value of 398, an exposure of 9.4s and a black level of zero (because the sky brightness will be enough to pull the histogram clear of the left hand side). The graphs below show useful detail on the calculations that help you understand the result and if necessary tweak the values.

The optimal exposure chart shows you the exposure time you need to use to hit your ‘Read Noise Limit’ criteria for different gains – it also shows your minimum and maximum exposure limits as horizontal red lines if they fall within the range of the graph. From this graph we can see that in this case the recommended exposure is 46.9s at 398 gain, but an exposure of 60s could be used at 230 gain or 30s at about 1400 gain to get very similar results. You aim for at least the exposure time shown on this graph, although selecting a longer exposure won’t improve things much as we will see in the detection threshold simulation chart.

The relative stack dynamic range chart shows how the dynamic range of the final stacked image will be affected by changing the gain (assuming you follow the suggested exposure time for each gain value). This chart shows information for different bit depths if the required sensor analysis data is available. In this case the stack dynamic range for the 8 bit line drops to zero at gains below about 450. This happens when there are no valid solutions for the exposure time that fit all the limits you have chosen – for instance in this case a read noise limit of 10% would require exposures longer thant the maximum exposure value of 5 minutes when in 8 bit mode with a gain < 450. In this case (in common with many cameras), you can get a slight increase in the dynamic range of the final stacked image by moving to lower gain values.

The third chart shows how the faintest visible object in the final stacked image varies with different exposure times. This chart makes it very clear how little extra you will achieve (other than pain in terms of guiding, tracking, hot pixels, satellite trails, aeroplane trails, etc) by exceeding the recommended exposure times. In this case at the recommended values, the expected faintest detectable object would be 0.0176 e/pixel/s. Increasing the exposure from ~47s to 300s drops that to 0.0168 e/pixel/s, an improvement of about 5%. You can also see that by this point the curves are basically flat – further increases in exposure bring practically no improvement to the final stacked image…

The Detection Threshold Simulation assumes that the faintest object you will be able to see in the final stacked image is equal in brightness to the noise level in that image. In fact, for objects that cover a large number of pixels, you might do a bit better than that as it is easier to see a large faint object than a small one, but this does not change the shape of the curve, in particular the fact that beyond the recommended exposure level there is practically no improvement in final image quality with further exposure increases.

In summary, when you use the Brain window, SharpCap simulates in a fraction of a second all the possible combinations of gain and exposure that you might use to image and calculates what the effect of each set of parameters would be on the final stacked image. This is possible because the results of the Sensor Analysis allow SharpCap to calculate the behaviour of the sensor for any combination of gain and exposure.

Smart Histogram requires a SharpCap Pro license and you must perform sensor analysis on each model of camera you intend to use. For best results perform sensor analysis in both 8 bit and high bit depth (12/14/16) modes.

Sensor Analysis

Ever seen those graphs provided by camera manufacturers of Sensor gain and read noise? Wondered how they were created? Well, they used to be a lot of manual adjustments and tedious measurements and calculations, but now SharpCap can perform those measurements automatically for you to generate a custom sensor analysis of your very own camera.

Why would you want to do that? Because the sensor data that is produced feeds into the SharpCap Smart Histogram functionality, which provides accurate guidance on the best gain/exposure to use for deep sky imaging based on the characteristics of your imaging sensor. With those numbers, SharpCap can perform a mathematical simulation of the amount of image noise that would occur in a whole range of different gain and exposure values and guide you to the ones that will give the best result.

Run a sensor analysis (Tools Menu) on your camera in RAW8 and RAW12/16 mode (or MONO8 and MONO12/16 for mono sensors) and SharpCap will save the results and use them to provide Smart Histogram guidance in future imaging sessions.

Note that SharpCap requires fine control over the camera exposure to perform Sensor Analysis – this means that it’s not possible on Webcams or Frame Grabbers. Also, if you have a colour camera it must be in a RAW mode to perform sensor analysis as the debayer process used to convert RAW images into RGB or MONO images causes sensor analysis to give incorrect results.

Sensor analysis is a free feature and does not require a SharpCap Pro license.

Feature Tracking

This lets SharpCap use your connected ASCOM mount (or ST4 connected camera) to guide the telescope and track on screen image features. Currently it is designed to work with high speed (Solar/Lunar/Planetary) imaging. SharpCap analyzes several frames per second and tracks movement of features between those frames – when the movement exceeds a threshold it will begin to make adjustments to bring the image back to it’s original position. An initial calibration step must be performed so that SharpCap can learn which way and how fast the image moves for the various mount movement directions.

Feature Tracking is currently experimental – please feel free to test and report any issues. More feedback on the performance with different mounts and focal lengths is welcome.

Feature Tracking is a SharpCap Pro feature and can be started from the Tools menu.

Seeing Monitoring and Auto Capture

This is a new application of the image quality measurement techniques that SharpCap has provided to assist focusing for some time. Instead of helping you find the point of best focus, you can now use the image sharpness measurements to help you capture the moments of clearest seeing without having to sit with your eyes glued to the computer screen at all times.

Launched from the Tools Menu, the seeing monitor shows a chart of the recent range of image quality with the most recent values highlighted. This gives a much more objective measurement of when the seeing is good.

Every new frame is analysed for sharpness (contrast) and the results are added to the graph that will build up below the image. You should select the area you are most interested in using the selection area tool (for instance sunspots, craters). Using the standard colour scheme, sharp frames build the graph in green on the right hand side, poor frames build the left hand side in red. If the seeing is relatively constant then you will see a graph like the one above with a single peak. If the seeing improves or worsens then a new peak will begin to build (to the right for improved seeing, to the left for worse seeing), like the image below. Note that other factors can also change the score and cause a new peak – for instance brightening or dimming caused by passing thin clouds.

SharpCap Pro users can additionally enable two automatic modes:

* Seeing triggered capture – this starts a capture when the seeing value exceeds a user picked threshold

* Seeing filtered capture – this will start a capture but only save the frames that exceed a user picked quality threshold

To enable these, you need to click on the graph to set a threshold level – this is the level which causes either capture to be triggered (when the image quality exceeds the threshold) or causes frames to be saved to file (when using the filtered capture).

Starlight Xpress Camera Supprt

SharpCap 3.1 now supports StarlightXpress cameras natively – no need to use the ASCOM driver any more. This provides better control over the camera and greater reliability. Please report any issues that you have with StarlightXpress cameras on the SharpCap forums.

Other Camera Updates

  • Updated SDK for Altair, Basler, Celestron/Point Grey, QHY and ZWO cameras to support new models and fix bugs
  • Support for QHY CCD cameras (QHY10 etc) that do not support video mode
  • Simplified support for Basler cameras – now a single camera choice provides the full range of available exposures, rather than having to choose between a Normal and LX mode option for the camera
  • Improvements to allow more Celestron/Point Grey cameras to work correctly.
  • Increased capture limits to a maximum of 100000 for sequence length and 999999 frames in a single capture (probably not useful both at once!)

Blind Plate Solving

SharpCap 3.0 contained integration to ‘Astrometry.Net’ based local plate solvers, but it required you to have a connected ASCOM mount as it used the mount pointing as an initial estimate of location to allow the plate solve to complete quickly. SharpCap 3.1 also contains blind plate solving (on the tools menu) which does not require a connected mount, it will just run your local copy of AstroTortilla/ASPS/AnSvr on the next frame and show the results in the notification bar.

Filename Templates

Lots of users have asked for little tweaks to be made to the way that capture files are named. Adding more checkboxes and dropdowns to the already complicated file naming tab of the settings wasn’t really an option, so instead I’ve added the ability to completely customize the file naming using filename templates. You’ll find these at the bottom of the filename settings tab and you’ll notice that the templates update automatically if they are disabled and you adjust other settings on the page, which will give you a good idea of what is possible for now.

One thing you may notice is that there is the option to include the current filter name in the filename using the {Filter} tag. If you are not using an ASCOM filter wheel then you can still use this feature by selecting ‘Manual Filter Wheel’ in the hardware settings – this will give you a filter wheel control in the camera controls panel which will not do anything except give a filter name to the file name template.

You can see that each filename template can be made up of tags which are wrapped in ‘{‘ and ‘}’ and text. The tags available include dates, times, camera names, target name, filter name, etc. Please note that using filename templates is an advanced feature and incorrect use can lead to files being overwritten – for instance if you do not include either ‘{Index}’ or ‘{FrameTime}’ in your Sequence template you will find that if you capture 100 frames in PNG format you will only get one file on disk because the file name for each frame will be the same and they will overwrite each other. Keep an eye on the ‘Sample Filenames’ above which show you the results of your templates.

SharpCap Max Memory

This new approach to memory management allows SharpCap to access considerably more system memory if it is available. This reduces the chance of running out of memory when working with high resolutions and allows SharpCap to cache many frames in memory when performing high speed captures (if the Hard Disk can’t keep up).

This feature is only available to users who have 64 bit versions of Windows and at least 4Gb of total system memory.

SharpCap Pro users can allocate up to 50% of their system memory to this feature, so if you have 16Gb of memory you could allocate 8Gb, which would allow SharpCap to cache nearly 6000 1280x1024xRAW8 frames in memory waiting to be written to disk! Non SharpCap Pro users can only allocate 2Gb to this feature, but that still gives a cache of 800+ frames available. The allocated memory needs to be split between high speed imaging frame cache and memory for other tasks such as live stacking on high resolution cameras.

Configure Max Memory settings in the ‘Memory’ tab of the SharpCap settings.

Live Stack Improvements

The Live Stack histogram has a had a significant facelift for this version

As you can see there are now separate traces for the different colour channels and colour balance adjustment sliders available if you are imaging with a colour camera. Note that the histogram always shows the levels of the stack held in memory, so adjustments to the colour sliders and the level stretch do not change this histogram (they do change the way the image looks on screen, how it is saved when using ‘save as seen’ and the mini histogram graph).

The adjustment of the display stretch is also improved and simplified by the removal of the various sliders in verion 3.0 and the addition of 3 simple draggable levels bars to set the black, mid and white points. You can drag these bars using the mouse. If you need very fine control of their position then hold down <SHIFT> while dragging sideways or move the mouse above the graph while dragging sideways – both will cause the bar to move more slowly and give finer control. An auto stretch button (the lightning bolt one) and a reset button complete the improvements to the histogram. It’s much easier now to control how steep the stretch is near the black point, which makes it easier to get good results when applying a strong stretch to faint nebulosity or galaxies.

On the stacking side, addition of a Sigma-clipping stacking option which will help reduce final stack noise and also keep artifacts like satellite, meteor and aircraft trails out of the stacked image (Pro Feature). Please note that changing between the default stacking algorithm and sigma-clipped stacking will reset the current stack. The ‘Stacking’ tab of the Live Stack panel gives some control over the options for the sigma clipped stacking.

There have been considerable improvements to memory usage during Live Stacking which will help with particularly on high resolution cameras. Users of high resolution cameras (10 megapixels or more) should use a 64 bit version of Windows with at least 4Gb of memory (ideally 8Gb+) for live stacking. Users of very high resolution cameras (30 megapixels or more) may need to increase the memory allocated to Live Stacking in the SharpCap memory settings. If PC does not meet this recommended levels then you may find that Live Stacking fails because it runs out of memory – a good workaround to this problem is to use your camera in 2×2 binned mode.

Note that the colour adjustment sliders, auto-stretch button and sigma clipped mode are SharpCap Pro features.

Polar Alignment Improvements

SharpCap 3.1 adds refraction correction to Polar Alignment – this means that SharpCap works out the error introduced by atmospheric refraction of light arriving from stars near the pole and corrects for it. To do this, SharpCap needs to know your correct latitude – this can be specified in the new ‘Polar Alignment’ tab of the settings dialog:

This allows you to turn refraction correction on or off and provide information on your location. If you use an ASCOM mount then SharpCap can retrieve the location from the mount, otherwise you can enter it manually or use the ‘Geolocate’ button if you can connect to the internet. Your location does not need to be exact – to the nearest degree will be fine!
SharpCap 3.1 also introduces some usability improvements to Polar Alignment to help you get great results – these include using a single star for the adjustment guidance (as long as that star stays on screen) and making sure that you don’t see any adjustment instructions until the final adjustment stage has been activated, since adjusting at an earlier stage gives incorrect results.

SharpCap now also tracks the apparent center of rotation position as the rotation angle is increased – this will help spot mechanical issues where the scope mount flexes significantly during rotation leading to poor results. In the images below you can see that the effect of a cable from the guide camera deliberately left unsupported is easily picked up by the red RA axis history crosses forming a line (left image). When the cable is properly tied up the measured RA points form a much tighter cluster (right image).

 Loose Cable
 Secured Cable

The pull of the weight of the dangling cable changes direction as the mount is rotated, moving the guide camera slightly and causing the apparent change in the measured position of the RA axis. To see the history traces for RA position you need to rotate the RA axis slowly (about 15 degrees at a time, then wait for a few frames – the RA axis trace will start to appear after the rotation passes about 30 degrees).
An increased polar alignment star database means that the initial position can be out to about 7 degrees from the pole (previously five degrees).

ASCOM device/camera Improvements

SharpCap 3.1 includes updates to improve compatibility with various ASCOM cameras/focusers/filter wheels and mounts. In particular, you should make sure that you install the ASCOM platform 6.3 (or newer) to get the best results.

A new option is now available in the hardware settings tab that allows you to configure SharpCap *not* to automatically connect to ASCOM hardware (focuser/wheel/mount) when a camera is selected. This is very useful if you do not always use your ASCOM hardware but want to leave it configured for when you do use it. In this mode, ASCOM hardware controls will appear in the control panel, but will not be enabled until the ‘Connected’ check box is ticked.

Other Improvements

  • Better control of the zoom level of the preview image. Zoom using the mouse wheel while holding the <CTRL> key down. No flicker of the image while zooming any more
  • Scroll the preview image using the mouse wheel if it is bigger than the display area – mouse wheel alone for vertical scrolling, mouse wheel + <SHIFT> for horizontal
  • Improved hot pixel handling in Dark Subtraction – SharpCap now analyzes the statistics of the dark frame to select a hot pixel threshold.
  • TIFF and JPEG file format output available. Note that JPEG files use lossy compression, so they will be lower quality images. Only use where image file size is important (ie all sky cameras)
  • Mean and Standard deviation readouts on the main histogram
  • Histogram crosshairs on the main histogram showing level, pixel count and further info if sensor analysis data is available

What has been REMOVED in SharpCap 3.1?

Windows Vista is no longer supported. This is because Windows Vista is too old to recognize the digital signatures that are now used to guarantee the authenticity of each build of SharpCap that you install. I thought it might be possible to make it work if Windows Vista had all possible Windows Updates installed, but I ended up spending 2 days waiting for it to install updates and at the end of that it was still ‘Searching for Updates’. I gave up, sorry.

The ‘old’ way of talking to webcams and frame grabbers that was used in SharpCap 2.9 and earlier (and was available as an option in SharpCap 3.0 – called the ‘DirectShow Pipeline’) is no longer available. Keeping this would have made improvements that needed to be made to the scrolling and zooming of the preview image harder or possibly even impossible.

LX modified webcams – Philips Toucam, SPC900, SPC880, etc – are no longer supported. Support for these devices was tightly linked to the old way of talking to webcams which has also been removed as noted above. If you wish to continue using these devices with SharpCap, please keep version 3.0 installed to support these devices. You can have version 3.0 and 3.1 installed at the same time.

What’s New in SharpCap 3.0

Well SharpCap 3.0 is finally here – it’s the biggest SharpCap release ever in terms of the amount of code written and the number of new features since the last version! This post gives a high level view of what’s new and changed since SharpCap 2.9 – more detailed description of these features will be coming soon in the updated SharpCap 3.0 User Manual.

SharpCap Pro

Perhaps the biggest change in SharpCap 3.0 is the introduction of the option to upgrade from the free version of SharpCap to SharpCap Pro. While the majority of the functionality of the program is still entirely free to use, some of the most advanced features now form part of SharpCap Pro.

SharpCap Pro licenses are available for the low price of £10 per year and give access to the following features

  • Real-time Flat Frame Correction
  • Dark Subtraction
  • Polar Alignment guided adjustment
  • Focus scanning and auto-focus assistance
  • Scripting

You can try all of these features (except the polar alignment adjustment) without buying a license – the only restriction is that once you have used these features without a license, saving is disabled until you close and restart SharpCap. Learn more about SharpCap Pro features here.

More exciting new feature will be added to both SharpCap Pro and the free version of SharpCap in future releases.

Hardware

On the hardware front, the big changes in 3.0 are the addition of support for Point Grey cameras and a revamp of how SharpCap handles Webcam and Frame Grabber input to bring those sources closer to the level of the dedicated astro cameras in terms of the functionality SharpCap can offer.

Point Grey Cameras

A big thank you to Astrograph for providing a sample Point Grey camera to work and develop with. Having a sample camera to develop against is pretty much the starting point for getting any new brand of cameras supported in SharpCap – without one it’s almost impossible to get things working in a reasonable amount of time. Currently SharpCap supports FlyCapture based cameras (not Spinnaker Cameras) and it should be fine with GigE, USB and Firewire models. As always, bug reports are welcome with as much detail as possible as it’s likely that different camera models might need a few more tweaks to the code throughout the beta process.

Point Grey camera support requires you to install some extra Microsoft components on your PC. To avoid making the SharpCap installer a lot bigger for everyone, these have been packaged separately in the ‘SharpCap PreRequisites Installer’. You can find this on the SharpCap Beta Downloads Page and you only need to install it once (not every time you upgrade SharpCap 3.0).

Webcam Improvements

The change to the processing of Webcam/Frame Grabber video is the other major change in SharpCap 3.0. Right from the first versions of SharpCap up until version 2.9, SharpCap has let DirectShow (the Microsoft Video components) take charge of showing webcam images on the screen and saving them to AVI file. As SharpCap has added more and more features for Astro cameras, Webcam users have been a bit left behind, since adding those features for them was either impossible or would have meant writing the code twice – once for Astro cams and once for Webcams. Now in SharpCap 3.0, SharpCap takes full control of displaying and saving the images from Webcams – DirectShow is only used for grabbing the image data in the first place. This means that features that couldn’t previously be supported for webcams are now available – these include

  • Dark frame subtraction and flat frame correction
  • Saving in SER or FITS format
  • Display adjustments of Gamma, Contrast and Brightness that affect the screen only

There is one drawback – if you have a camera that captures in a compressed format (primarily MJPG, possibly I420, YUV, YUY2 etc), then the new approach will lead to bigger capture files as the output files are always saved as RGB (three bytes per pixel). In this age of cheap SSD storage and even cheaper hard disk storage, it’s unlikely that the increase in file size is going to cause a problem, but if it does you can switch back to the old way of doing things in the settings dialog.

Camera SDK Updates

SharpCap 3.0 contains new versions of the camera SDKs from the major Astro camera vendors (Altair, QHY, ZWO) which fix bugs, add support for new models and add new features. If you have a new model camera from any of these vendors you may well find that it will work better with SharpCap 3.0 than it does with SharpCap 2.9

Other Hardware

SharpCap3.0  adds direct support for ZWO EFW filter wheels without needing to have ASCOM installed. There is also now an option on each type of supplementary hardware (Focuser, Filter Wheel, Mount) to allow the hardware to be temporarily disconnected then reconnected while the camera is running.

Image Processing

Flat Frame Correction

Flat frame correction is a brand new feature in SharpCap 3.0 – it allows flat fields to be captured in the same way that previous versions of SharpCap assisted in capturing dark frames and then the flat field can be applied to correct each image captured, correcting both the image viewed on screen and the data saved to file.

SharpCap uses the special high speed CPU instructions that are usually for games and multimedia to allow flat frame correction to be carried out at very high speed. With a modern high power processor you should be able to apply flat frame correction to the video stream from a USB3 camera (like a ZWO ASI174MC) at full speed.

Thanks to Gary Palmer for his suggestions and discussion that led to the creation of this feature.

Dark Frame Subtraction Enhancements

SharpCap 3.0 adds the ability to create and apply high bit depth (16 bit) dark frames when using 8 bit cameras (or 8 bit modes). This is important when using live stacking with low gain (low noise) as otherwise the repeated use of an 8 bit dark frame negates the improvement in signal that would be expected as the number of stacked frames increases and the SNR of the stack increases.

Live Stacking Improvements

This version of SharpCap adds a filter option for for frame brightness which can be used to reject frames that are dimmer than the average – this should allow detection of incoming or patchy clouds. Additinally there is a new tab showing history graphs of the rotation and offset of each frame in the stack to allow a better understanding of how well the mount is tracking.

Lots of other improvements have been made to live stacking to improve both performance and user experience, including

  • Ability to soften the black point of the histogram stretch to give better image tones around the black point
  • More options to tweak the parameters used for star detection
  • Improvements to file naming so that the total stack duration is included in the file name
  • Warnings shown if a number of frames in a row are not stacked for some reason

Finally, SharpCap no longer re-detects stars in the stack every time a new frame is added, meaning that the time taken to stack each frame is approximately halved!

Focus Assistance

SharpCap 3.0 adds focus assistance if you are using an ASCOM focuser. This appears in the ‘Graph’ tab of any of the focus measurements if you have a focuser connected. Rather than having to adjust the focuser through several positions one at a time to find the best position you can use the ‘Scan Out’ and ‘Scan In’ buttons to perform a series of measurements of the focus score. Once a scan has been performed and has a maximum (or minimum) score in it, you can use the ‘Goto Best Positon’ or ‘Goto Best Score’ buttons to put the focuser back to either the position where the best score was measured or to seek the best score value.

The ‘Goto Best’ buttons both take the focuser back to the beginninng of the scan so that the best score is approached in the same direction to avoid backlash problems.

You can use the ‘Options’ button to adjust the size and number of steps used when scanning.

Plate Solving

SharpCap now supports plate solving using AstroTortilla, All Sky Plate Solver or AnSvr if you already have one of them installed on your computer. You’ll need to have AstroTortilla itself  (or ASPS or AnSvr) installed (including the Star Index files).

You can kick off plate solving using the locate button (GPS Symbol) in the mount control (you have to have selected an ASCOM mount to access the plate solving). When you press the locate button, the current frame will be plate solved, the mount will be synced to the solution and then will perform a re-GOTO to the position it was originally supposed to be pointing to.

Polar Alignment

Some significant improvements have been made to the star detection algorithm used when polar aligning, which means that 3.0 can find enough stars to plate solve in situations where SharpCap 2.9 struggled. In addition, SharpCap 3.0 uses the latitude and longitude of your ASCOM mount (if connected) when determining the direction to adjust the pointing of the polar axis – that should give more reliable directional indications.

UI Improvements

The UI has been refreshed in some areas with a new Splash screen and many simple message boxes being replaced by more informative task choice dialogs.

SharpCap had some issues up to and including version 2.9 if you had changed the Windows colour scheme to a high contrast scheme – In a number of areas of the program, text would appear as black on a black background! These issues are fixed in SharpCap 3.0, so the program can be used properly with a high contrast colour scheme.

Control groups now have colour coded headers, helping your eye (and mouse) go to the group you are looking for more easily.

Other Improvements

SharpCap scripting is improved by the inclusion of a full python standard library so that it’s no longer necessary to use the .NET API for basic tasks like file I/O in scripting. It’s now possible to run an RPC server like Pyro inside SharpCap to allow SharpCap to be controlled by other applications. Unfortunately due to limitations in Pyro it’s not possible to directly exposre the SharpCap object model, but it’s possible to write Python objects to wrap the SharpCap object model and expose those objects.

As astro-imaging has evolved, sensor sizes and pixel counts have increased vastly from the 640×480 webcam sensors that were typical when the first versions of SharpCap were released. Now sensors with 6, 10 or even 20 megapixels are not uncommon and these place a bigger load on your PC’s memory and CPU. SharpCap 3.0 brings improvements to memory usages (particularly for live stacking) that should improve performance when working with very large sensor sizes. It’s still a good idea to have plenty of memory (8Gb+) and a 64 bit version of Windows if you want to use SharpCap with high resolution cameras.

SharpCap performance in general has been improved, with the time taken for the application to start reduced by up to 50%.
An enormous number of issues and minor bugs have been fixed in SharpCap 3.0 (thanks to those who have beta tested the various builds and sent in crash reports).

Finally, SharpCap 3.0 adds the – long requested – ability to manage capture profiles, which includes the ability to delete unwanted profiles and to set/clear the default profile for each camera.

SharpCap 2.10 Beta

The first beta build of SharpCap 2.10 is now available on the Beta Downloads Page. Once again 2.10 is a very big release and there are a lot of new features and an awful lot of bug fixes and improvements.

Hardware

On the hardware front, the big changes in 2.10 are the addition of support for Point Grey cameras and a revamp of how SharpCap handles Webcam and Frame Grabber input to bring those sources closer to the level of the dedicated astro cameras in terms of the functionality SharpCap can offer.

Point Grey Cameras

A big thank you to Astrograph for providing a sample Point Grey camera to work and develop with. Having a sample camera to develop against is pretty much the starting point for getting any new brand of cameras supported in SharpCap – without one it’s almost impossible to get things working in a reasonable amount of time. Currently SharpCap supports FlyCapture based cameras (not Spinnaker Cameras) and it should be fine with GigE, USB and Firewire models. As always, bug reports are welcome with as much detail as possible as it’s likely that different camera models might need a few more tweaks to the code throughout the beta process.

Point Grey camera support requires you to install some extra Microsoft components on your PC. To avoid making the SharpCap installer a lot bigger for everyone, these have been packaged separately in the ‘SharpCap PreRequisites Installer’. You can find this on the SharpCap Beta Downloads Page and you only need to install it once (not every time you upgrade SharpCap 2.10).

Webcam Improvements

The change to the processing of Webcam/Frame Grabber video is the other major change in SharpCap 2.10. Right from the first versions of SharpCap up until version 2.9, SharpCap has let DirectShow (the Microsoft Video components) take charge of showing webcam images on the screen and saving them to AVI file. As SharpCap has added more and more features for Astro cameras, Webcam users have been a bit left behind, since adding those features for them was either impossible or would have meant writing the code twice – once for Astro cams and once for Webcams. Now in SharpCap 2.10, SharpCap takes full control of displaying and saving the images from Webcams – DirectShow is only used for grabbing the image data in the first place. This means that features that couldn’t previously be supported for webcams are now available – these include

  • Dark frame subtraction and flat frame correction
  • Saving in SER or FITS format
  • Display adjustments of Gamma, Contrast and Brightness that affect the screen only

There is one drawback – if you have a camera that captures in a compressed format (primarily MJPG, possibly I420, YUV, YUY2 etc), then the new approach will lead to bigger capture files as the output files are always saved as RGB (three bytes per pixel). In this age of cheap SSD storage and even cheaper hard disk storage, it’s unlikely that the increase in file size is going to cause a problem, but if it does you can switch back to the old way of doing things in the settings dialog.

Camera SDK Updates

SharpCap 2.10 contains new versions of the camera SDKs from the major Astro camera vendors (Altair, QHY, ZWO) which fix bugs, add support for new models and add new features. If you have a new model camera from any of these vendors you may well find that it will work better with SharpCap 2.10 than it does with SharpCap 2.9

Other Hardware

SharpCap 2.10 adds direct support for ZWO EFW filter wheels without needing to have ASCOM installed. There is also now an option on each type of supplementary hardware (Focuser, Filter Wheel, Mount) to allow the hardware to be temporarily disconnected then reconnected while the camera is running.

Image Processing

Flat Frame Correction

Flat frame correction is a brand new feature in SharpCap 2.10 – it allows flat fields to be captured in the same way that previous versions of SharpCap assisted in capturing dark frames and then the flat field can be applied to correct each image captured, correcting both the image viewed on screen and the data saved to file.

SharpCap uses the special high speed CPU instructions that are usually for games and multimedia to allow flat frame correction to be carried out at very high speed. With a modern high power processor you should be able to apply flat frame correction to the video stream from a USB3 camera (like a ZWO ASI174MC) at full speed.

Thanks to Gary Palmer for his suggestions and discussion that led to the creation of this feature.

Dark Frame Subtraction Enhancements

SharpCap 2.10 adds the ability to create and apply high bit depth (16 bit) dark frames when using 8 bit cameras (or 8 bit modes). This is important when using live stacking with low gain (low noise) as otherwise the repeated use of an 8 bit dark frame negates the improvement in signal that would be expected as the number of stacked frames increases and the SNR of the stack increases.

Thanks to Matt from Astro Video Systems for suggestions that lead to the introduction of this features.

Live Stacking Improvements

This version of SharpCap adds a filter option for for frame brightness which can be used to reject frames that are dimmer than the average – this should allow detection of incoming or patchy clouds. Additinally there is a new tab showing history graphs of the rotation and offset of each frame in the stack to allow a better understanding of how well the mount is tracking.

Lots of other improvements have been made to live stacking to improve both performance and user experience, including

  • Ability to soften the black point of the histogram stretch to give better image tones around the black point
  • More options to tweak the parameters used for star detection
  • Improvements to file naming so that the total stack duration is included in the file name

Finally, SharpCap no longer re-detects stars in the stack so far every time a new frame is added, meaning that the time taken to stack each frame is approximately halved!

Focus Assistance

SharpCap 2.10 adds focus assistance if you are using an ASCOM focuser. This appears in the ‘Graph’ tab of any of the focus measurements if you have a focuser connected. Rather than having to adjust the focuser through several positions one at a time to find the best position you can use the ‘Scan Out’ and ‘Scan In’ buttons to perform a series of measurements of the focus score. Once a scan has been performed and has a maximum (or minimum) score in it, you can use the ‘Goto Best Positon’ or ‘Goto Best Score’ buttons to put the focuser back to either the position where the best score was measured or to seek the best score value.

The ‘Goto Best’ buttons both take the focuser back to the beginninng of the scan so that the best score is approached in the same direction to avoid backlash problems.

You can use the ‘Options’ button to adjust the size and number of steps used when scanning.

Plate Solving

SharpCap now supports plate solving using AstroTortilla if you already have it installed on your computer. You’ll need to have AstroTortilla itself installed (including the Star Index files).

You can kick off plate solving using the locate button (GPS Symbol) in the mount control (you have to have selected an ASCOM mount to access the plate solving). When you press the locate button, the current frame will be plate solved with AstroTortilla, the mount will be synced to the solution and then will perform a re-GOTO to the position it was originally supposed to be pointing to.

Other Improvements

SharpCap scripting is improved by the inclusion of a full python standard library so that it’s no longer necessary to use the .NET API for basic tasks like file I/O in scripting. It’s now possible to run an RPC server like Pyro inside SharpCap to allow SharpCap to be controlled by other applications. Unfortunately due to limitations in Pyro it’s not possible to directly exposre the SharpCap object model, but it’s possible to write Python objects to wrap the SharpCap object model and expose those objects.

Finally, SharpCap 2.10 adds the – long requested – ability to manage capture profiles, which includes the ability to delete unwanted profiles and to set/clear the default profile for each camera.

Downloads

Beta builds can be downloaded here.

What’s new in SharpCap 2.9.2877?

 

  • Polar Alignment – improved plate solving algorithm – faster, more robust
  • Polar Alignment – more options for tweaking star detection
  • Live Stacking – Add option to save separate image files for each stacked frame
  • Live Stacking – Reset button to reset histogram controls
  • Altair Cameras = Updated SDK – add Gamma and Colour Balance to RAW mode
  • QHY Cameras – Add support for controlling cooler on cooled CMOS models
  • QHY Cameras – Better support for filterwheels connected via camera
  • QHY Cameras – Updated SDK – Add support for new models
  • ZWO Cameras – Default into RAW mode not RGB (consistent with other colour Astro cameras)
  • ASCOM Cameras – fix bugs with loading capture profiles
  • Celestron/Imaging Source Cameras – fix frame progress showing incorrectly
  • UI – Allow different heights for different lower panels
  • Increase memory allocated to frame buffers to better support large resolution cameras (ZWO1600, QHY183 etc)
  • Various other bug fixes

 

SharpCap 2.9 Now Available

SharpCap 2.9 has perhaps had more work go into it than any previous version of SharpCap – certainly I’ve changed the code more times (409) than ever before for a new version. As well as the addition of the completely new Polar Alignment functionality, there have been big improvements to Live Stacking, Focus Score measurement, Dark Subtraction and many other areas of the product. In a little more detail…

Download Links

New Feature:

  • Polar Alignment – select Tools -> Polar Align and read the on-screen instructions

Live Stacking:

  • Save to 16 bit fits by default (32 bit option in drop down)
  • Many options now persisted
  • Pause button added to temporarily stop adding new frames
  • Better file naming
  • Add digital gain and other new star detection tweaks.
  • Stretching changed to a simple gamma stretch with white/black levels
  • Histogram stretch settings automatically saved/restored
  • Negative pixel values supported in the stack which improves dark frame subtraction effectiveness
  • Fix dark subtraction in live stacking when using RAW capture mode

Focus Score:

  • History Chart completely re-written – more detail, more interactive, can now pan & zoom
  • Add new focus score measurement based on image contrast range
  • Add new focus score measurement based multi star FWHM
  • Add new Fourier Transform Focus Score
  • Add smoothed trace to bar chart
  • Add mean value to bar chart when using an ASCOM focuser
  • Add new graph of score vs position when using an ASCOM focuser
  • Remember size/position of selection area
  • Bahtinov mask focus score now has standard history chart like other score methods

Cameras & Hardware:

  • QHY Cameras – Updated SDK – Support QHY5III cameras
  • ZWO Cameras – Updated SDK – Fix bugs and support new models
  • Altair Cameras – Updated SDK – Fix bugs and support new models
  • Celestron Cameras – Updated SDK – Fix bugs and support new models
  • Test Cameras – Improved planetary test camera
  • RAW Mode – Option to force debayer pattern in raw modes for cameras that lie about their pattern
  • Hardware – Mount control via ST4 support added on ZWO, QHY, Altair cameras (Experimental)
  • Hardware – Focuser Control – You can type a value in the focuser position box

UI:

  • Fix remembering size of docked controls and other UI bugs
  • Add hot keys for Quick Capture (Alt-Q), Live Stack (Alt-L), Snapshot (Alt-A)
  • Control Panel – Groups can be re-ordered with drag and drop. Order saved per camera, can be reset from Options menu
  • Old style UI controls and the options to enable them removed
  • Auto option added to the Zoom drop down that will fit the frame in the available space
  • Reticules – add more outer rings on the circular reticule – helpful for collimation
  • Show countdown of frames being written to disk at end of capture
  • Histogram – do not show jagged histograms in 10/12 bit modes
  • Histogram – option to choose between Logarithmic and Linear vertical scale
  • Histogram – Exclude the value for the blackest level to avoid a big spike at that point in linear mode
  • Histogram – Fix vanishing histogram bug

Misc:

  • Scripting – many improvements and bug fixes to enable more use of Python scripting
  • File Naming – creates sequentially numbered files instead of multiple files called 0001 in different directories
  • File Naming – more informative name for single frame captures.
  • Dark Subtraction – Fixes to dark subtraction applied incorrectly in RAW mode
  • Dark Subtraction – Fix colour order wrong in dark stacks on colour cameras
  • Dark Subtraction – Fix dark creation in 16 bit mode (was half intensity)

Bug Fixes:

  • Bug fix – polar alignment with non-English numeric settings
  • Bug fix – incorrect bayer pattern saved to SER file when using horiz/vert flip on ZWO cameras
  • Bug fix – ensure only a single frame is captured when taking a snapshot on high speed cameras
  • Bug fix – focuser in/out buttons were not working
  • Bug fix – fix issue where memory could become exhausted if the UI became bogged down
  • Bug fix – changing colour space could sometimes cause a crash
  • Bug fix – capture time limit display incorrect
  • Bug fix – number of frames captured during dark capture and other limited frame captures was incorrect
  • Many other minor bug fixes