So I have, since being a kid in the early '80s, wanted to shoot a few DSOs on film and check that off my bucket list.
I have a roll of E100 and a Pentax K1000, appropriate t-ring, and a shutter release cable. I have some substantial experience shooting with DSLRs and astro cameras, landscape, deep sky and planetary/lunar.
I want to take some images with both my Stellarvue 80mm APO and my 8" Celestron SCT.
I have a .63x (gets more like .68x on the 8") Starizona FR/CC for the SCT, and a .65x Starizona FR for the Stellarvue. These are both good to an APS-C size only.
1) If I shoot with the APO and FF (no FR) only, it should be good to full-frame (35mm). I am thinking on some brighter DSOs 20-30 minutes at F/6 oughta get me something?
2) The APO with the reducer shoots at a pretty fast ratio, but I'd need to crop a scanned image because the field brightness would fall off and the stars would start to elongate substantially. Is this a reasonable thing to try with something like a galaxy? Speed traded off for loss of field? I am assuming similar principles apply to film emulsion molecules as to pixels?
3) A similar question applies for the SCT. Endemically it's F/10, and SCT fields aren't great at the edges anyway. I am assuming I could apply similar logic to the reduced SCT as for the reduced APO regarding cropping a final scanned slide image?
I am aware of reciprocity failure, that if I was really going to do everything the best way possible I would hypersensitize the film and shoot with a cold camera. Unless you all tell me I'll get no result without doing those things, I want to keep this all as simple as possible.
I don't think I'll be able to catch Orion nebula this year because of weather, but if this goes at all well, I may try again next year.
Other targets I am considering: M81, M51, M45, any other good suggestions coming up in the sky through next month?
Thanks for any advice!