Switch to windows explorer. This is the photo having the gradient issue.

0. This is the photo having the heavy light pollution gradient at the down left side

Duplicate it!

1. Duplicate the original photo

Click on this menu item to duplicate it.

2. Duplicate the original photo

Yes, you did it.

3. The photo has been duplicated

Now start Photoshop

4. Load both photos in Photoshop

Take care. Remove the signal.

5. Wip out the signal i.e. the nebula. Do not wipe out the gradient. Use the copy stamp tool

Photoshop has many filters. You need one of them.

6-Use Gaussian Blur in PS

Use 51 percent blur.

7. The Mask is ready

8-Click on Bild_Bildberechnungen. i.e. Photo_Calculations

Substract the mask you created from the original light polluted photo.

9. Select the menu Bild_ Bildberechnungen (clalculations) and subtract the gauss mask from your photo

You can make this out of it. You can eliminate the gradient problem and get a photo like this.

0b. There is solution for that problem! You can eliminate the impact of the light pollution by using this guide. Read how to eliminate the gradients in your photos.

Ready! Now compare both photos!

10. This is the result Left: The clean photo AFTER the processing. Right: The polluted photo BEFORE the processing.

You begin here. Your photo has a serious problem.

0a. The problem is visible. There is an ungly gradient at the left down side of the photo. It is caused by the light pollution.