Starlight Xpress 694C issues in post processing - HELP! :-)

[JayS_CT]

I have the Atik version of that camera which I tend to use at star parties for the simplicity it offers.

I don't use darks for calibration.
I find this chip needs a good soaking. My subs for galaxies are typically 10-15 minutes.Matrix for debayering is GRGB BUT you do need to be careful how you have the .fits setup in PI against how they are written by you capture software. I have PI setup as UP_BOTTOM
If you don't use Darks you will need to include Cosmetic Correction in the workflow to deal with warm pixels BEFORE debayering unless you are using a very large dither. Warm pixels on an OSC turn into little crosses when debayered. Interpolation during alignment will then 'smear' these into warm blobs that can be 5 or 6 pixel artefacts. A dither therefore needs to be at least 5 pixels to allow them to be rejected during stacking.
You will ALLWAYS need to colour calibrate. Light pollution and LP filters, atmospheric extinction etc will always throw the colour balance off kilter. PI has brilliant tools for CC.

My base workflow is Calibrate (Bias and Flats) > Cosmetic Correction > Debayer > Align > Stack > Crop > DBE > Background Neutralisation > Colour Calibration > Stretch

Chris,

Thanks for all the great info.  I'm on a Mac and using AstroImager. I also have SkyX which I've used in the past for DSLR but will image with it as well. I am getting a Matrix of GRBG (not GRGB) from FITS read in SkyX.  Read about Cosmetic Correction but never used it.  Can you expand on the PI UP_BOTTOM reference.  Again I'm coming from a totally DSLR perspective to PI. These were shorter exposures but agree the camera can take longer exposures given well depth.  Have not seen too many "little crosses" after Debayering (yet).  Also plan to add Dithering on next run.

Given your knowledge and the download link, could I impose and ask if you could take a run with the data there?  Again, my "biggest" issue right now is the Color side and getting those blues and reds.  :-(  Looking at Maxim DL which others have recommended but the workflow doesn't seem intuitive (but I'm a total novice there).

Appreciate again..

Jay S.

[chris.bailey]

Jay

I do all my capture with SkyX. It is important that all files used for processing come from the same capture program, especially so with OSC files.

Up-Bottom or Bottom-Up define the co-ordinate origin of the .fits file. Normally it doesn't matter too much but with an OSC file the bayer matrix changes as the image is effectively flipped vertically. I used RGGB for your files. A good tip is to point your setup at a colourful daytime object and run off a few files and keep them somewhere safe. Much easier top see if the colours are about right that way.

Your files do have quite a few warm pixels so CC is very worthwhile.

A very quick and dirty run using the workflow I mention other than step 1 - Calibration as you can't calibrate with debayered masters. Its nice data, a bit more time and other methods of stretching would have retained a bit more star  colour but you get the idea.

Chris

[JayS_CT]

Jay

I do all my capture with SkyX. It is important that all files used for processing come from the same capture program, especially so with OSC files.

Up-Bottom or Bottom-Up define the co-ordinate origin of the .fits file. Normally it doesn't matter too much but with an OSC file the bayer matrix changes as the image is effectively flipped vertically. I used RGGB for your files. A good tip is to point your setup at a colourful daytime object and run off a few files and keep them somewhere safe. Much easier top see if the colours are about right that way.

Your files do have quite a few warm pixels so CC is very worthwhile.

A very quick and dirty run using the workflow I mention other than step 1 - Calibration as you can't calibrate with debayered masters. Its nice data, a bit more time and other methods of stretching would have retained a bit more star  colour but you get the idea.

Chris

Chris,

Thanks for this..  Will give it a try!  Thanks also for generating an image..

Jay

[JayS_CT]

Jay

I do all my capture with SkyX. It is important that all files used for processing come from the same capture program, especially so with OSC files.

Up-Bottom or Bottom-Up define the co-ordinate origin of the .fits file. Normally it doesn't matter too much but with an OSC file the bayer matrix changes as the image is effectively flipped vertically. I used RGGB for your files. A good tip is to point your setup at a colourful daytime object and run off a few files and keep them somewhere safe. Much easier top see if the colours are about right that way.

Your files do have quite a few warm pixels so CC is very worthwhile.

A very quick and dirty run using the workflow I mention other than step 1 - Calibration as you can't calibrate with debayered masters. Its nice data, a bit more time and other methods of stretching would have retained a bit more star  colour but you get the idea.

Chris

Chris,

Wanted to get your thoughts on Assisted Color Calibration?  When I messaged with Starlight Express, they indicated when processing with Maxim DL that values of 110 R, 100 G and 130 B would be applicable with the 694C.  This looks like a "similar" place to account for that white balance adjustment.  Thoughts?  Reading of the processing of it, it recommends unstretched images during use (if I'm reading it correctly).

Jay S.

[JayS_CT]

Jay

I do all my capture with SkyX. It is important that all files used for processing come from the same capture program, especially so with OSC files.

Up-Bottom or Bottom-Up define the co-ordinate origin of the .fits file. Normally it doesn't matter too much but with an OSC file the bayer matrix changes as the image is effectively flipped vertically. I used RGGB for your files. A good tip is to point your setup at a colourful daytime object and run off a few files and keep them somewhere safe. Much easier top see if the colours are about right that way.

Your files do have quite a few warm pixels so CC is very worthwhile.

A very quick and dirty run using the workflow I mention other than step 1 - Calibration as you can't calibrate with debayered masters. Its nice data, a bit more time and other methods of stretching would have retained a bit more star  colour but you get the idea.

Chris

Chris,

Thanks for this..  Will give it a try!  Thanks also for generating an image..

Jay

All,

Thanks..  Now, if I can only make sure I can repeat it!  :-)

Jay S.