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Old 02-09-2014, 10:33 AM
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Peter.M
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Join Date: Sep 2011
Location: Adelaide
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Quote:
Originally Posted by Shiraz View Post
Hi Pete. Sorry, I guess I have rabbited on a bit

I think we agree, but....

If by "exposing for longer" you mean "exposing subs for longer", there is no value in longer subs. For example there is no SNR difference between a 20 minute sub and the average of 2x10 minute subs if both are "sky limited". The differences are that more stars will be saturated in the 20 minute sub, (so you have lost dynamic range) and the chance of a dud sub is higher (eg due wind gust or clouds). The issue is not that long subs are inferior from an SNR perspective, just that once you have subs that are long enough to be "sky limited", the SNR after stacking is the same from short or long subs - but you will lose in other areas by going longer.

If by "exposing for longer" you meant overall exposure, there is obvious benefit from going longer.

I did mean exposing each subframe for Longer.
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