DEIMOS has a 13 position slitmask cassette to hold user slitmasks. Positions 1 and 13 are left empty for mechanical reasons and one position is occupied by the focus mask GOH_foo. This allows the user to specify up to 10 slitmasks at one time be in DEIMOS. Many observers prefer to install a long slit in place of one mask in case of a mask failure. Selecting the slitmask usually is done directly from The Dashboard GUI; however, one may select their slitmask from the SLITMASK PANEL dialog shown above.
The slitmask subpanel includes a dremel button in the lower left corner which bring up the dremel subpanel, which is used by the observatory staff to scan slitmasks; it should not be used by the observer.
Afternoon setup for DEIMOS takes on the order of 2 hours, but is eased by the checklists and many automated scripts. Please check out the Slitmask Imaging Tool, the Slitmask Alignment Proceedure, and the Slitmask Calibration Tool.