# hw7_sol - /usr/bin/env python Joseph Harrington AST...

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#! /usr/bin/env python # Joseph Harrington # AST 5765/4762 # Homework 7/8 # 21 October 2007 # Updated 20 Oct 2008 by Kevin Stevenson # Updated 1 Oct 2009 by Joseph Harrington # Problem 1 # S is signal # N is noise (standard deviation) # t is total integration time # n is number of integrations # i is integration time of 1 frame # r is the read noise # S = tF = niF # Poisson photon noise is sqrt(S) = sqrt(niF). # In addition, there is read noise from EACH readout: # N**2 = sqrt(niF)**2 + n r**2 = niF + n r**2 # N = sqrt(niF + n r**2) # S/N = niF/sqrt(niF + n r**2) # i = 5 # n = 10 # S/N = 50*F / sqrt(50*F + 10*r**2) # i = 50 # n = 1 # S/N = 50*F / sqrt(50*F + r**2) # Since noise is the only consideration here, it is better to take one # 50-second integration, so that there is less read noise. The Poisson # noise is the same in the two situations, as is the signal. # Taking one integration also avoids the time needed to read out the # array nine additional times (so it is more time-efficient), and it

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hw7_sol - /usr/bin/env python Joseph Harrington AST...

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