You should absolutely feel free to collaborate on this homework!!! Task #1 =========================== Measure the mean and standard deviation (i.e., "sigma") of the counts in the individual bias frames from our practice photometry dataset. Task #2 =========================== Measure the mean and standard deviation of the counts in the master bias from our practice photometry dataset. What is the ratio of these two types of standard deviations (from Task #1 and Task #2)? Task #3 =========================== Measure the mean and standard deviation of the counts in the *sky regions* of a157.fits. How do they compare to those found in Task #2? Task #4 =========================== Measure the gain and read noise from our practice photometry dataset. Gain = [ (+) - (+) ] / [ (sigma_F1_F2)^2 - (sigma_B1_B2)^2 ] RN = Gain * sigma_B1_B2 / sqrt(2) where = average of a flat field image = average of a second flat field image = average of a bias image = average of a second bias image sigma_F1_F2 = standard deviation of F1-F2 sigma_B1_B2 = standard deviation of B1-B2 Task #5 =========================== Measure the brightness (in magnitudes) via photometry on 5 field stars in a157.fits. See the attached for which 5 field stars in particular. Use the PHOT package within noao/digiphot/apphot. Remember the following commands: spacebar -- do photometry :ap X -- change aperture to X :ann Y -- change inner sky annulus to Y :dan Z -- change sky annulus thickness to Z To do PHOT within IRAF, you'll definitely want to have your desktop environment be able to "bring up" the window whenever your mouse hovers over that window ... Task #6 =========================== From: Chip Kobulnicky To: ddale Subject: reduction note Date: Fri, 6 Jun 2014 04:35:27 -0600 dd, after we had to restart claudius (another freeze) the somehow temp did not get set to -110, instead it got left at -140...so the night's data was taken that way. We took a set of dawn flats and biases at this temp. It would be interesting to compare (ratio) the flats and biases to those taken at -110 on other nights. It may not make a difference...but it might. I'll be interested to know the results, as well as the results of comparing dome flats on 5/29 to skyflats. Left as an exercise to the student...