Hi everyone,
I’m new to SharpCap and still trying to understand the best workflow for live stacking. When stacking a faint deep-sky target, do you normally let it run for a fixed amount of time, or do you stop when the image stops improving noticeably?
I’m also wondering whether there is a point where adding more frames can actually make the result worse because of changing conditions, guiding errors, or passing clouds.
Any beginner tips on what you normally watch while a stack is running would be appreciated. Thanks!
New to SharpCap – how do you know when to stop live stacking?
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Re: New to SharpCap – how do you know when to stop live stacking?
Hi,
I think it is mainly a matter of personal taste - the noise will gradually reduce and at some point you will either feel it is gone enough to be happy with the image or you will run out of darkness/clear sky/wakefulness/time until the meridian and have to stop for one of those reasons.
It's good to remember that the reduction in noise is something that is fastest in the first few frames of the stack and gradually slows down after that. By four frames it is half the noise of one frame, by 16 frames it halves again, by 64 it halves another time and so on (256, 1024, etc). Note that each time it takes four times as many frames just to halve the noise. This makes the improvements tail off pretty quickly.
One thing to remember is that for faint targets from light polluted regions, a lot of the noise comes from the light pollution - dealing with that by using appropriate filters or finding a dark skies spot to image can help massively.
cheers,
Robin
I think it is mainly a matter of personal taste - the noise will gradually reduce and at some point you will either feel it is gone enough to be happy with the image or you will run out of darkness/clear sky/wakefulness/time until the meridian and have to stop for one of those reasons.
It's good to remember that the reduction in noise is something that is fastest in the first few frames of the stack and gradually slows down after that. By four frames it is half the noise of one frame, by 16 frames it halves again, by 64 it halves another time and so on (256, 1024, etc). Note that each time it takes four times as many frames just to halve the noise. This makes the improvements tail off pretty quickly.
One thing to remember is that for faint targets from light polluted regions, a lot of the noise comes from the light pollution - dealing with that by using appropriate filters or finding a dark skies spot to image can help massively.
cheers,
Robin