Flat and Dark-Flat details

The following things happen:

• Move the scanner to the inital position (always center?)
• Initialize the camera
• Set up the fits header (done in the Photometrics memory)
• Close the shutter
• Continuous-clear command to camera
• Turn on the flat light
• Move the stage on
• Send "expose" command to camera
• Open shutter
• Pause for the exposure time
• Close shutter
• Turn off the light
• Go to cache 2 and send "bias" to ccd
• Pause during exposure time (same time as flat)
• Move the stage back
• Write cache 1 (flat) and cache 2 (dark-flat) to tape.