Uncertainty Computation

astro07 wrote on May 16, 2007

I have some data taken last year in which I combined eight 10 second exposures by averaging them together. The problem is, the star I'm looking at is very faint. When I take the error generated by IRAF using phot and divide it by the square root of the number of images, I get an error which I know is too low. I think it's because the readnoise is actually a big factor in the uncertainty. Do you know of some way I can account for this?

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Last post on May 16, 2007