Hello, recently I have been trying to photograph star trails at night with my nikon D810. I thought I had everything right, tripod, remote shutter etc. But I kept getting this weird red fuz on the left side of my image. I then tried using my nikon d7100, and there was no red fuz. I was wondering if my nikon d810 has some sort of technical issue that needs to be repaired or it is some setting.
Attached is one of the images with the issue.