I collected all these photons on the ring nebula

[stepping beyond]

A astro friend has been helping me with some of my processing because he uses the same as I do and he's even stumped from over 3,000 miles away . PROBLEM 👨‍🦽 I'm having trouble getting up this hill and it's not for lack of trying to work through the problem. I'm trying to layer a cropped ring , over a background image and everytime I attempt it in Photoshop cs2 following the steps { image windows side by side and click n  drag the cropped image over } I never get the right size ring even when both are at 100%. I've been working on this for 2 weeks and still no change the ring is still too small . HELP ?

[michael8554]

Were The Ring and the background stars shot with the same equipment, in other words do they both have the same field of view, and the size width and height in pixels ?

Then both need to be cropped by the same percentage,  so that the stars image includes only the stars in The Ring image.

If from different sources:

Crop The Ring and note the width and height in pixels.

Crop the stars image so that only the same stars as in The Ring image are included.

In the Image Resize or equivalent tool, set the new size of the stars image to be the same as The Ring size previously noted.

Layer them, you now have a cropped Ring and cropped stars that match in size.

Michael

 

[stepping beyond]

Ok , Michael  that sounds easy enough but, if I want the Ring blums of nebulosity added to my Ring image how would I pull that off ?

[michael8554]

With the stars on a lower Layer, and The Ring on the top Layer:

Lasso a Selection just outside the blooms of nebulosity.

Create a New Mask Layer of that Selection.

Add Gaussian Blur to the edges of the Mask until The Ring merges seamlessly with the stars.

Adjust black level to match stars and Ring backgound levels.

Michael

 

[stepping beyond]

Sounds good , I'll  give it a go when I start to get some cloudy nights but, right ow it's clear for the past week.