FITS header for better external solving


Very simple and not really a big deal:

SGPro currently puts SCALE in the FITS header for the pixel scale. A lot of external solving engines (, PinPoint, NOVAS, as a few) will look for PIXSCALE in the header to help determine the pixel scale for solving. This doesn’t matter to SGPro as it passes the scale to the solver directly (I believe). If others get an SGPro FITS image the solvers don’t have the pixel scale.

Anyway we could add PIXSCALE (or PIXSCALE1/PIXSCALE2 to follow standard axis speak) to the FITS header for SGPro in addition to the SCALE?

For instance, pass -g to as additional command line, and it will read the pixel scale from the FITS header.


We can definitely add PIXSCALE, but PIXSCALE1 and PIXSCALE2 are illegal header names.


Opps. PIXSCAL1 and PIXSCAL2 but I think PIXSCALE is enough. Thanks.


I am not seeing focal length or aperture in the fits header in I see that there is a settings button in the telescope setup dialog that leads you to the ascom dialog where you set aperture, focal length, and obstruction - and I would really like all that info in the fits header if it is available. I see pixsize is there, and I guess if I did a plate solve it would fill in SCALE - but this is basic info about the telescope itself that is very useful to have in the fits header - so please include it. I use external solvers and do photometric analysis, and the images are usually not solved by SGP - so it is important for the header to capture this info.




Please make a proper request for this (a new topic, not at the end of someone else’s topic… as it is likely to be lost) and we will consider it for future releases.

You can enter the scope’s focal length in the telescope tab in the CP (this will make it the the FITs header). We currently have no construct to capture and persist aperture and obstruction.


Ugh - now I see it there. I could have sworn it used to save the focal length - and now I do see it in the control panel. But aperture and secobs are also needed for photometry.

I will enter a separate request for aperture and secobs.