Harvard-Smithsonian Center for Astrophysics
XRT E2E Test
Day 20050606 Shift A
Test Conductor B. Podgorski
Shift Scientist J. Cirtain
Initial Remarks Concerning XRT E2E Testing
The CCD was cooled to operating temperatures. Testing commenced about 13:30 CDT today. The operating temperature of the telscope was set to be 15 C. The CCD temperature was -40 C and was allowed to stablize before the testing commenced. We collected first light images and determined that there was a 4 pixel shift in positive x when the FAM was turned on due to a small change in the encoder positions. We also were able to determine that a 16 second exposure was appropriate for the tests and was well below the saturation limit.Best Focus I --- Coarse Scan
A scan at focus positions spanning the entire focus range was performed and 2D gaussians were fit to the images for each focus position. There were 21 such focus positions. A number of images from this scan are provided below as well as a plot of the RSS gaussian widths as a function of focus position. The latter plot shows the best fit second order polynomial that fit the data. The minimum in the data was found to be at -750 focus steps. This was chosen to be an approximation of the location of Best focus. After this determination was ccomplete a fine focus scan about this position was performed. See Shift B
