I switched the observatory camera from the original CCD SBIG ST-10XME to my modified CMOS Canon 500D/T1i. Replacing the observatory camera was more work, of course, than envisioned. The Canon sensor is set back compared to the SBIG and there was not room for the TEC-140 telescope to get focused. Jeff Dickerman, the super helpful president at Optec, made me a new adapter to go with another receiver that shortened the camera train enough to get easily into focus. I then rediscovered (I had forgotten but found my own forum entry) that CCDAutoPIlot had to turn off the feature on TheSkyX that would record both RAW and FITS files and records only the FITS files. It turns out the DeepSkyStacker can work with FITS and convert the RAW files that create them in color. But I had over time come up with a dark library in RAW frames for the Canon so I could temperature match with the light frames. I don’t have such with FITS files. But if I want to use the observatory automation of CCDAutoPilot, which I do, I will need a new FITS library at a range of temperatures to do it right.
Then I had trouble with setting exposure with CCDAutoPilot on the Canon images. I’m telling a lot of technical info here, but it took a lot of wrestling directly with complex technology to get through all the unforeseen obstacles. The Canon CMOS sensor uses a 2X2 Bayer matrix to record color. Two cells of the matrix are green, the other two are red and blue each. CCD’s, like my SBIG camera,have individual sensors not organized in a matrix. In something to do with the CMOS Bayer matrix, CCDAutoPilot only sees one cell as exposed, and it was saturated, while the other three were only about one-fifth exposed. It averages them in a meaningless way and it seems hit or miss if CCDAutoPilot can get the exposure close enough to get flats. Sometimes it gives up, sometime it settles on something. Focusing is tough too, as is plate solving. CCDAutoPilot did not have a solution as you can see on their forum here, but John Smith there encouraged me to investigate on my own further. You are getting in pretty deep when the software designer basically says good luck.
Weirdly, after all that, I did come up with the image below.Continue reading