Figure 43.1: WF/PC-1 Optical Configuration
In total, the WF/PC-1 contained eight relay mirror-repeater-CCD trains, four for the wide-field camera and four for the planetary camera. To place the desired camera into operation, the pyramid was commanded to rotate into one of two fixed orientations separated by 45 degrees. The Wide Field cameras (WF) produced a final focal ratio of f/12.9 while the Planetary Cameras (PC) produced f/30.
Two readouts for each camera were available: FULL and AREA mode (given in the MODE header keyword). FULL mode was the default, with full single-pixel resolution. In full mode, each line of science data contained two 16-bit words of engineering data followed by 799 16-bit numbers as read from the chip, followed by 12 overclocked pixels which were used to determine the bias level (BLEV) correction (see "Calibration Details" on page 45-7. During the initial steps of the routine pipeline processing, the science data was reformatted and separated into the raw (.d0h/.d0d) science data (800 x 800 pixels) and the engineering data along with the 12 bias columns (.x0h/.x0d).
AREA mode-which was not used often (only 50 images, 35 of them externals, out of 15,746 total WF/PC-1 images)-was a 2 x 2 pixel summation. In this case, the two words of engineering data were followed by only 400 16-bit numbers read out from the chips; no overclocking was done. In this mode, the BLEV correction was determined from the second column of engineering data. The least significant bit (from odd rows only, even rows contained engineering data) was averaged, then multiplied by two.
Figure 43.2: WF/PC-1 -Field of View on Sky