Night blindness is, physically, a loss of sensitivity of the rods in your retina, and since the chemical rhodopsin ( manufactured from Vitamin A) is the chemical responsible for photoreceptivity, it can be helped somewhat by eating foods rich in Vitamin A. But for a persistent condition, as an astronomer, there isn't much you can do about it. Amateur astronomers rely on being able to orient themselves by the constellations so that they can point their telescopes, and night blindness would make this very hard if not impossible to do. If you own one of those fancy computer-controlled telescopes, you still need to align the darn thing by finding Polaris. But, if someone else has a telescope, you should be able to look through the eyepiece and see stars and planets and the moon OK..except you probably will not see nebulae and galaxies very well. Using binoculars and low-power telescopes will amplify the star light enough to overcome part of your night blindness provided that your condition isn't too severe.