Long Slits: Standard long-slits are available for Nod & Shuffle observing. These utilize the central third of the detector for science, the top and bottom thirds are used for charge storage. The longslits are listed on the GMOS long-slits page. Requests for long-slit configurations other than these will be handled as multi-object spectroscopy and the user must design the masks using the procedures described below.

Multi-Object Spectroscopy (MOS) Masks and the Maskmaking Software GMMPS: The mask-making software supports the design of Nod & Shuffle MOS Masks for both micro-shuffling and band shuffling. Details are available on the MOS pages.