Quote:
Originally Posted by Slawomir
That's very useful, thank you Ray. I will try your method to determine optimal sub length for my gear, as I relied on SGP or PI for doing that for me, with varied success. Also, I can't wait to actually take my telescope out - it has been ages...
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Quote:
Originally Posted by Camelopardalis
Great stuff thanks Ray, I was thinking of experimenting with some narrowband from the city so that gives me something to grapple with. I expect I'll be sky limited pretty quickly by the looks of it  |
it isn't actually my idea
- M&T did the same sort of thing earlier in this thread and it seems to go back as far as these papers at least:
http://www.hiddenloft.com/notes/SubExposures.pdf
http://www.stanmooreastro.com/eXtreme.htm
it is a good way to work out how your system is performing and theory behind it is the basis for the various optimum sub-length calculators and also the "Really Easy" method.
yeah Dunk, if you have read noise of say 2e, you only need about 6e shot noise to overwhelm it - and you get that from just 36 photoelectrons, which is really miniscule - it won't take long under bright sky. In fact there may be a case for going for longer than optimum just to keep the processing load down - the only thing you will lose is dynamic range.