I stacked 6 images in PS to get detail and good focus for all of the rock keyhole and blended with I image of the Milkyway. The moon was ~ 20% and setting on this night which lit the rocks very nice. My WB for the Milkyway was set to 3800 in camera.

This keyhole faces ESE and the Milkyway is in the south when it rises above the horizon in Aug. To get this composition I had to set my tripod up in such a way that the legs were different lengths to get my camera against the rock. There was no wind so the tripod was steady. There was a lightning storm on the horizon in the NW that fortunately never stretched to the south. It was a magical night at a magical location in western Kansas. The chalk pyramids are on private property and being on location past daylight requires special permission and I was grateful to be granted this permission.