Longer exposures by stacking

[Guest]

I don't have any guiding on my scope at the moment. I can get the tracking reasonable so that 1 minute exposures don't show too much drift but I would like to do a ten minute exposure to get a brighter image. A 10 minute exposure does show significant drift. So I wondered if there was a way of doing say ten x one minute exposures and stacking them to give give me the equivalent of a ten minute exposure in terms of image brightness. 

[scitmon]

You might need to explain what you mean by "image brightness" more...

The only thing you need to worry about (at least for now) is that your 1 min exposure's histogram is not clipping on the left. i.e. you see something like this

 

 

If that is the case, then you can stack and post process to bring out details.

Edited May 14, 2020 by scitmon

[ollypenrice]

What you are suggesting is exactly what all deep sky imagers do. There is a somewhat precise debate over whether 10x1 minute equals 1x10 minutes. With CCD cameras it doesn't, but this is not a debate for entry-level imaging. With cooled CMOS cameras with low read noise, it more or less does. DSLRs lie somewhere in between. Who cares? You should do it.

The free way to stack lots of short exposures is to use Deep Sky Stacker. It works. It isn't used by the majority of imagers trying to produce work at the top of the amateur scale but it is very competent and entirely free.

You want brighter? We all do!  What you need is more signal (from the object) and less noise (from the camera.) A lot of the noise is random but the signal is consistent. If you stack 20x1 minute you get 20 doses of real signal and 20 doses of random noise. The noise will cancel itself out, being random. The signal will build. Result!

Olly