Harvard-Smithsonian Center for Astrophysics
XRT E2E Test
Day 20050609 Shift A
Test Conductor B. Podgorski
Shift Scientist J. Cirtain
Wings of the PSF at Best Focus
Collection of data for the wings of the best focus PSF was completed. We took nearly 100 images at the current best focus position (-515 um). Most of these images were summed 8 x 8 to increase the signal to noise. As was expected, the core of the image was saturated, and attempts were made to pull the wings of the PSF out from the background noise. This will be an on-going effort.
It became necessary to determine the appropriate number of images to use when summing the successive images taken during this subtest. A plot of the mean of the summed images outside the masked PSF core as a function of number of summed images was porduced, and is provided below. Apparently, the signal associated with the wings of the PSF is of the same order as the background noise. When summing a substantial number of these images the background dominates the wings. The result of the plot shown below is that the number of minimum entropy assosicated with the signal in the wings relative to the signal from the background is 14. This concludes the analaysis completed on the wings of the PSF during the E2E testing. Further analysis will be performed post-test for after flight calibration of the data. A histogram of the cross-section through the core of the PSF shows how small the signal for the wings of the PSF really is...
