This number maps the file to one of the CCD locations on the focal plane, as indicated in Figure 2. The table linked below shows the proper sky orientation for each chip as it is displayed onscreen. CCD display orientation chart Gain and read noise parameters for LFC CCDs Fig. 1 -Photograph of the LFC focal plane inside dewar. 2 -Schematic of the focal plane layout, displaying the CCD numbering convention.
Large circle shows the illumination pattern of the corrector .
Two LFC filters mounted in their respective cartridges. The metal rule measures 10 inches. At a given time, four filters may be mounted the wheel. There are 4 additional LFC sized filters in use with the instrument. Two of these are a pair of narrowband filters owned by R. Ellis, and the other two are custom prescription R and I filters for C. Steidel.