To what extent is deep space photography considered overexposed?

The background of the image is white. Deep space photography uses precision instruments such as equatorial mounts to take partial photos of celestial bodies. Many "whole-body photos" and partial photos of celestial bodies in textbooks are taken using this method. When the image background appears whitish, it is considered overexposed. Overexposure refers to the whitening of photos that are too bright in the picture due to factors such as too large aperture and too slow shutter speed.