Deep Sky Stacker tip.

[Greenman]

If you find problems adding darks or flats to DSS ensure you are using the same program to collect the lights and calibration files.
Otherwise you may be puzzled why you are unable to stack the calibration files and get a warning that there are incompatible files due to colour, size etc.

I collected on my ASIAir and did the calibrations with SharpCap. Has taken me a bit of time to track down the issue. Different programs produce files with enough difference to cause this error.

Hope this saves someone searching the web for ages…

[bobharmony]

Thanks for pointing up one of the quirky things about DSS, Tony - I'll add another. If you modify an calibration frame that was created by the same program as your lights, you may receive a similar message and DSS refusing to use them.

A couple of years back I tried rotating my darks by 180 degrees to compensate for a meridian flip, and got the same error message about image size from DSS. I deal with it now by turning off the auto-orientation change option in the camera setup. It is there to help when you rotate the camera 90 degrees for a daytime photo that you want in portrait mode rather than landscape - but can be an issue for AP calibration frames.

Bob

[seigell]

These are both common issues with AP Capture Programs:

1. Some programs capture the Entire Sensor to the Output FITS or RAW (including the masked-off calibration pixels) and others only capture the "visible pixels". This produces output files of differing dimensions with no information on what might be "discardable".
2. Some Capture Apps apply the Camera Orientation information to the file before outputting it, while others more correctly record that info to the EXIF Orientation field and leave the image as original. Similarly, some users will use a FITS-TIFF or RAW-TIFF Conversion Routine that takes action on the Camera Orientation rather than simply transfer that EXIF data to the output file. (Pre-stacking file conversions are dissuaded as they often apply Gama or Stretching or Debayering - all of which cause serious problems with the Calibration and Stacking to be performed in DSS or PI or APP or other program.)

Neither of these are a fault of DSS, no more than inputting poor Lights or Calibration files or poor focus or poor guiding...

[Greenman]

These are both common issues with AP Capture Programs:

1. Some programs capture the Entire Sensor to the Output FITS or RAW (including the masked-off calibration pixels) and others only capture the "visible pixels". This produces output files of differing dimensions with no information on what might be "discardable".
2. Some Capture Apps apply the Camera Orientation information to the file before outputting it, while others more correctly record that info to the EXIF Orientation field and leave the image as original. Similarly, some users will use a FITS-TIFF or RAW-TIFF Conversion Routine that takes action on the Camera Orientation rather than simply transfer that EXIF data to the output file. (Pre-stacking file conversions are dissuaded as they often apply Gama or Stretching or Debayering - all of which cause serious problems with the Calibration and Stacking to be performed in DSS or PI or APP or other program.)

Neither of these are a fault of DSS, no more than inputting poor Lights or Calibration files or poor focus or poor guiding...

I wasn’t referring to it as a fault in DSS, it is however undocumented in the manual as to what could cause the issue. That led to a scramble through the internet to resolve the problem (as a relative beginner at DSO work). I was unaware of the issue for that reason; and your information is useful as an aside.

I don’t at this point have many of the answers, or indeed most of the questions.