Stacking

[Ganymede12]

I'v heard that stacking images can improve their quality. So what do you have to do to stack images and do you need multiple different images to stack or can you re-use the same image?

[Keiran]

To start you need a bit of stacking software, I use DSS (Deep Sky Stacker) it is free, and works very well. Secondly you need to take as many subs (images) as possible.

Stacking an image will allow you to build up all of the detail from an object you are imaging. There will be some really faint data in all of the images you capture. and stacking all of these on top of each other will enable you to pull all of that data out. It will allow enhance all of the brighter detail you have.

[Black Knight]

It's a pretty straightforward process as well. Click on Open your picture files and select your image files (and your darks and flats ), check all the files, and then click register checked pictures. By default, DSS will stack your registered subs automatically when registration has completed.

[Ganymede12]

Thanks for the info but one question remains. Do you have to take different photos of can you just copy one photo multiple times?

[SionR25]

You have to take different photos. The same one just has the same details being stacked so doesn't really improve what you already have.

Sion

[Ganymede12]

Thank you!

[stolenfeather]

I do my stacking using video files. RegiStax does all the work and the end result is fabulous!

Isabelle

[Ant]

It's all about signal vs noise.

Noise will generally be the same in each image, but noise is random.

The stacking process effectively cancels out the noise - because it's not in every frame (in the same place) and enhances the signal because it is in every frame in the same place.

There is more to it than that, but it gives you an idea.

Ant

[Ganymede12]

What is noise and signal (in regard to images)?

[SionR25]

Noise is just a random discolouration or brightening of pixels. Happens most at high ISO settings and is more noticable in darker photos. Because the noise is random, by taking multiple shots you can get rid of the affected pixels.

Signal, I think, is the actual detail that you want in the image, E.G. the features you are trying to capture. A bit unsure on this though as I haven't heard it being called that before.

Sion