Quote:
Originally Posted by JA
Long story short... Buy the Askar 400 and use one of you existing cameras if you want, but to me that is a waste. You are buying a short focal length in order to use your existing cameras, but you are throwing away a lot of light using the smaller sensors. It defeats the purpose of having multiple telescopes imaging the same field since you are not using anywhere near the entire full-frame sized image circle of the Askar 400.
It would be far better in light collection terms for you to forget those smaller scopes and instead focus you attention on a larger sensor for your 90mm f/6 if it is a good quality unit. That way you can get a larger field of view without another scope. This could be done with an APS-c sensor on your 90mm f/6, possibly using a focal reducer or using a
full frame sensor, possibly even try a modern DSLR/mirrorless camera rather than expensive (re your budget) astrocam. This would collect ~4 TIMES THE LIGHT of the 4/3 inch sensors. Having 4 times the light is like having 4 telescopes.
If it were me, within your budget, I would get a modern full frame mirrorless DSLR, probably a Nikon Z5 or Z6 or Sony A7models /Canon to use on your 90mm f/6 to do RGB imaging and consider a L-extreme filter to use with it if you want to try narrowband. Or you could save / extend your budget to allow you to purchase an APS -c sensor with or without a reducer.
Best
JA
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How should or could i answer you??!!!
Well, i have many DSLRS, some of them are full frame cameras, NONE of them came close to my cooled cameras, even my non cooled planetary cameras are doing better than any of my DSLRs or one mirrorless camera for DSO, so i will never waste time with a DSLR or mirrorless, and i will never send one for modify it for astro and i have no brave at all to do it by myself, so DSLR and mirrorless are out of questions.
Now about the image circle of the scope, this is nothing to worry about or care about, because i can always use that for another targets, and one day i might buy another APS-C in mono, but for now i have smaller sensors cameras, people are using them with whatever scopes, so it is no point from you to tell me to forget about them, and not all astrophotographers using full frame astro cameras or even APS-C, so i have those small sensor cameras then i must use them, and for FOV i want using astronomy.tools site it showed me what focal length i should buy to use those cameras for certain FOV i want, so cameras are staying, i have to buy scopes to give me those FOV, ASKAR FRA400 isn't only designed for full frame, also not all people who have this FRA400 using full frame or APS-C, so why they bought that, in fact even people who bought Takahashi FSQ-106 also some of them using small sensor cameras where the scope is even larger than full frame image circle.
Long story short is making this more complicated, my 90mm triplet is nice quality and designed for full frame also, if i buy a reducer that will make it down for APS-C, and i think not FRA400 but another scope with a reducer will cover up to APS-C, so using smaller sensor won't be a big deal, are you telling me now to have all my scopes designed for full frame and i should have all my cameras as full frame or APS-C???
I have to use multiple scopes, but i hate hate hate to use only one scope for whole imaging data per target, i remember i used my Canon 135mm lens at F2 wide open for Orion collecting HaLRGB, i spent 3 nights for that and the data was bad due to CA, so even F2 didn't help it to make it fast, i will never spend my life doing each target for 3 nights or more, and i will never spend more only to get RASA when a lens at F2 didn't help it as well, so i try to pick up several/some targets and try to collect data from multiple scopes, but i think using multiple scopes is like a bad idea from so many people, in this case no one will understand or help in this case, i saw few used multiple scopes for amazing successful results, each has own FOV or setup, i want to do mine for that wide field for now.