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Unformatted text preview: UCF Physics: AST 5765/4762: (Advanced) Astronomical Data Analysis Fall 2009 Lecture Notes: 15. CCD Corrections 1 Check In: 12:30 12:35, 5 min Questions before we start? 2 Summary of CCD Systematics: 12:35 12:40, 5 min QE < 100% QE varies I d I d varies pixel to pixel I d varies in time (with temp, etc.) I d has its own noise V bias Read noise Amplifier not perfectly linear Pixels not perfectly linear! Too much charge cancels some bias voltage. Cosmic rays deposit many e- in wells Some pixels have defects (bad pixels) 3 Basic CCD Error Correction: 12:40 12:45, 5 min Do readout backwards: QE differences were multiplied, so divide them out Dark current was added, so subtract it Bias voltage was added, so subtract it Basic formula: C = R B D F (1) 1 4 Making the Calibration Frames: 12:45 12:55, 10 min This is an art! Sensitive analyses and quirky instruments more robust methods Here are the basic principles Bias frame: average many 0-exposure images, B = 1 N B i Dark frame: D = 1 t tot...
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This note was uploaded on 11/09/2009 for the course AST 4762 taught by Professor Harrington during the Fall '09 term at University of Central Florida.
- Fall '09