hi i was using my D50 for taking pictures of the stars, then my cousin used his D80. he told me that the D50 had a better sensor for shots of the sky, but i didnt understand why. for 20 min exposures his pictures were coming out green, and mine were working fine. he also told me that for long exposures the sensor could get hot. is that true? if he ever sends me the pictures i could show u the green ones.