HO W TO… combine exposures
For better starscape shots, you’ll need to delve into Photoshop and blend exposures for the sky and land
Start working on the sky frame in Lightroom, using exactly the same sliders as in the single frame method. Adding Vibrance and/or Saturation is personal preference and a little can be added if desired.
If you adjust white balance for the sky frame, make sure the same values are added to the foreground frame or the two images will look different. Once these adjustments are made, send both images to Photoshop as layers.
Edit in Photoshop
With the foreground as the top layer, add a layer mask and carefully brush in the sky. Adjust the brush opacity, and go back and forth around the horizon until there is a seamless blend, and the foreground and sky appear uniform.
Both sections of the image can be edited as separate entities; try an additional subtle S-curve adjustment to the sky. When happy, flatten the image, then proceed to clean out any unwanted artefacts before cropping.