dark clears the CCD mosaic, waits for the stated time and reads out the CCDs, saving the images as four runs in FITS files. The files are passed to the archiving and logging facilities.
The command handles the necessary interactions with the shutter and autoguider. The shutter is closed before the CCDs are cleared and remains so during the timing and the readout. At the end of the readout, the shutter opens again to let the autoguider see the sky. If the system is autoguiding at the start of the run, it will autoguide again after the run finishes.
A title may be given for the observation: the title appears as the datum of the OBJECT keyword in the FITS headers and as the target name in the observing log.
dark time ["title"]where time is in seconds. The title-string must be enclosed in double quotes.
Each run generates four FITS files, each with a different run-number. For a particular file, the name of the CCD that produced it may be recovered from the FITS keyword CHIPNAME and the CCD number (1..4) from DASCHAN.