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


  • 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


  • 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