I'm basically trying to plot some images based on a given set of parameters of a .fits file. However, this made me curious: what IS a .fits array? When I type in img[2400,3456] or some random values in the array, I get some output.
I guess my question is more conceptual than code-based, but, it boils down to this: what IS a .fits file, and what do the arrays and the outputs represent?