I shoot RAW + Jpegs but only cause wifie hates to process Raw files. Sorry to tell you but I'm betting you have to shoot Raw files plus process the sky as an extra step to bring out stars.I'd import into PS thru Bridge 2 copies of the same image. Copy 1 I'd adust in Raw for the foreground exposure (that washes out the sky), copy 2 I'd adjust in Raw to bring out the stars.
Then I'd sandwich the 2 with the sky over the foreground, _dupe_ both layers, add another (layer 5) foreground, fill bottom layer with white _only_, this will layer is handy for cropping.
Now you got bottom to top, white canvas, foreground (hide this), Sky (hide also), foreground 2, Sky 2.
Now hide the sky and work on Forgound - color, brightness, etc. DO NOT correct size or perspectives yet! Switch to Sky, color, brightness, etc.
Switch back to foreground, hide sky. Select the elements you like, own tool or lasso, etc. Invert the selection and delete. DO NOT Deselect yet. Switch to Sky, invert and delete. Save that selection just in case. Save as PSD at this point.
Now if you're happy you can merge to processed foreground + sky and correct the size and perspective. The white canvas may show thru to enhance the stars but I've found it useful at the perspective correction above.
Happy again? You did work on copies, not originals, didn't you? Flatten, sharpen for print or view, save as Tiff, save as JPEG. Done.
That's a work flow I adopted, painfully, YMMV of course. Happy Phtoshopping.
Cvt
Sent from my Pixel XL using Tapatalk