I've been experimenting with my E-130 after putting it back into service, so I thought I'd image something familiar and I chose M42. But being a bad scientist, I put more than one experimental variable into play. I wanted the advantage of RGB color, but I only have an OSC DSO camera. My idea (hairbrained or otherwise) was to shoot both RGB subs and white light color subs and see if I could find a way to put all of that data together. Because the scope is fast (f/3.3) I didn't take dark frames and because the camera signal is so clean I eschewed bias frames, too (the scope is so fast that even 10 s exposures kind of blew out the Trapezium region). I had flat frames on file, but the field was not vignetted or mottled at all so I didn't need to use them (I did use hot and cold pixel filters in stacking). The images were all unguided because the mount is so good and the exposures short. The skies were not very transparent and not as dark as usual (Bortle about 4). The exposure data are
frames/ length/ time each
30/ 30 vis long/ 900
25/ 10 vis short / 250
30/ 30 blue long/ 900
25/ 10 blue short/ 250
30/ 30 green long/ 900
25/ 10 green short/ 250
30/ 30 red long / 900
20/ 10 red short/ 200
20/ 30 Ha long / 600
20/ 10 Ha short/ 200
total 255 5350 total sec
89.16666667 total min
1.486111111 total hr
In summary, I had to work really hard to get a fairly decent image out of the data. As the exposure data indicate I also took a set of Ha images to bolster the HII emission in the nebula. I think this hybrid method I tried is a workaround until I can afford a mono camera, but it is very image processing-intensive! And, as fate would have it, Elon, the friend of all astrophotographers (not!), released a batch of his StarLink satellites over our area that day. As the images updated on the screen, it was not uncommon to have one, two or even three satellites showing up! Their tracks were faint enough to not be a problem, for anyone shooting a faint subject, they will matter!