Astro Noise Elimination

[ameerat42]

Guys.

I am trying to reduce noise in astro images (so far the moon) by taking a series of shots and then...
combining them somehow. I thought a stacking program would be the go, but is it? What is a good
method to use that retains some reasonable detail?

Ta.

[Glenda]

I wouldn't have thought your ISO would get high enough to cause noise problems when photographing the moon. I know people who stack star shots to remove noise and have looked at it https://www.youtube.com/watch?v=Rydg7JGTAbw but personally I've always just used plug ins such as Nik's define or Topaz's denoise.

[ameerat42]

Ta. Very interesting tute, Glenda. Will dissect it again later.

[nardes]

Hi AM

I have noticed that stacking say, 10 DSLR frames does allow you to push the data more aggressively and still retain smooth tonal transitions with natural looking detail.

With just a single frame, I find too much aggression in processing introduces unnatural tones and sharpening artefacts.

I am lucky that I can shoot at ISO100 on a tracking mount so it is relatively easy to grab 10 frames (Live View to minimise mirror slap).

I load the 10 frames into PS CC and set the Mode to Difference and then nudge each one (if required) to align at the pixel level. This is not always possible as the atmospheric scintillations can cause details to "wander" or "morph" between frames. Sometimes the EDIT ALIGN function in PS CC does an excellent job too.

Once you are satisfied that you have several frames nicely Aligned in PS CC, I then combine them as a Smart Object (Layers Menu) and then use the Smart Object (Layers Menu) to stack them either using Mean or Median.

Cheers

Dennis

[ameerat42]

Ta, Dennis. I have been looking at what my hmble CS2 can do. Some of the functions mentioned aren't there
as scripts, etc. Meanwhile, I have employed CZM stacker to do the aligning, and... [it's a work in progress].