Terminate an exposure early, saving data and headers to disk.
2=to: 2!:}Format: FINISH <channel>
2=to: 2!:}Channel: The name of the CCD data acquisition channel to be used.
2=to: 2!:}Examples : FINISH PFIP
2=to: 2!:}Comments: This command terminates the current CCD exposure, saving the data to disk as if the exposure had completed normally.