Most astroimagers know that if you take lots of frames and combine them, you get better results. The classic formula states that the gain in signal-to-noise ratio is equal to the square root of the number of frames combined.
But I have found that this is too simplistic. A lot of the time, we didn’t have the best sky to work with or we misjudged exposure times. I used to think that a combination of the longest exposures and the most frames would give the best results. And in a perfect world, that would be true.Astronomy magazine subscribers can read the full column for free. Just make sure you're registered with the website.