A bit of a noise problem here.

[gregmeister_admin]

I shot this image a few days ago and have done very little to it in terms of color or any other adjustment for that matter. It has been cropped because getting the horizon level at Midnight with no moon is a good trick for old eyes...

What I want some help with is the noise. I have struggled with the noise in this frame and want to keep detail as much as possible.
This was shot at f/5.6 ISO 1600 and 30 seconds. I used noise control in camera but it is still very noisy especially in the blue channel which I replaced with a copy of the green.

I'll post my original as well as a copy with the green channel copied.
Greg

[gregmeister_admin]

Raw conversion to Jpeg. Nothing more.

[Ganna]

Greg, I gave it a shot. For the sake of others, I will write down what I did.
With thanks to a tut of Kristina Sherk on the Kelby one website: I partly did what she said:
I took your first image, the one with the blue-channel modified.
1. Used the Nik filter Define2 (on auto)
2. In CS6: Layers>convert to smart objects
3a Filter>reduce noise (low strength)
b. Secondary filter:>Bur>surface blur (Radius 6 and Threshold 9)
4. Blend-if to preserve sharpness in the bright areas; ( the stars )(move white slider 80% to the left)
Thats it. Sure with time consuming masking it can be improved

[artmar]

(Began with your original image)
Topaz DeNoise
Stamp Visible
Topaz Clarity
Stamp Visible
High Pass filter (blend mode Hard Light, 25% opacity)
Save

(Darker sky but lost a lot of the red color compared to Martin's version...)

[Ganna]

Second attempt with Topaz Studio and last step with CM
I tried to give it a more "dreamy" effect... was night time

[gregmeister_admin]

On a lark I tried NIK Dfine2 from the older NIK collection.
Here are the results from a basic pass at the noise.

I have to say I was pretty pleased overall. There is some noise but it is much reduced without too much softening of the image.

G

[DougS]

All corrections seem pretty good, did what I would have done, doubt I could do any better.

In sky night images for noise correction, I always use a luminosity mask to preserve the stars from getting lost with noise reduction.

This is a good tut on doing so using Lumenzia plugin which is an excellent tool too, along with CM.
https://www.youtube.com/watch?v=J3v8M4zE6yg

Doug