GMOS can perform broad band imaging (using the SDSS filter system) or narrow-band imaging using select filters. The field of view is 5.5 arcmin x 5.5 arcmin (and does not cover the entire CCD package), with two ~ 2.8 arcsec (39 pixel) gaps between the detector chips, as shown below (GMOS-S, GMOS-N original EEV CCDs and upgraded e2v DD devices). To cover the gaps it is recommended to use dither steps of at least 5 arcsec in the X-direction. The size of the gaps in the upgraded GMOS-N Hamamatsu detector package is expected to be similar, and will be determined when the CCDs are commissioned. See the Status and Availability webpage for more details.