gradient issue

[DaveD]

In the photo below you can see a vertical line next to the small moon for Saturn. The line is the right edge of the Jupiter photo.
I'm trying to figure out why it is doing this
I would have to go to the Jupiter pic and put a layer mask on that and erase the edge part over (behind) Saturn

 

[IamSam]

The line is the right edge of the Jupiter photo.
I'm trying to figure out why it is doing this

Because the edge of the gradient on the layer mask is not complete.

Here I have placed Saturn behind Jupiter using a layer mask. I made the selection with the Elliptical Marquis Tool.




It would work the same If you wanted Jupiter behind Saturn................you may have to use the Brush tool for the rings.