stcking photos in astrophotograpghy
someone asked me about stacking astro photos. heres a quick primer.
when you shoot astro you have to get as much exposure as you can while eliminating random noise.
rather than shooting one super long exposure you can instead shoot a lot of shorter exposures and then using a process called stacking combine them. this allows you to bring out the details int he image while greatly reducing noise.
if you think about it noise is random. so if you have 2 photos of the same thing and some pixels are lit in one photo and not the other theres a good chance thats noise and can be eliminated. thats teh basis pf stacking.
after stacking the photo will have the detail in it but it ahs to be edited to bring it out from the background. this is called stretching. your basically stretching teh histogram so the details take center stage
heres an example. this is my shot of bodes galaxy. Its 160 2 minutes exposured stacked together for a total of 5 hours and 20 minutes of exposure.
the first shot is one exposure straight from the camera. the galaxy is there but barely visible
after stacking and stretching
the same idea can even be applied to subjects like the moon. in that case your trying to eliminate distortion caused by the earth atmosphere which also tends to be random
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