NEW! GMOS-S detector array has been upgraded. CCD1 and CCD2 have been replaced by new Hamamatsu chips (of similar type to the original ones). The commissioning is ongoing, as it had to be interrupted due to the cybersecurity incident. It will be resumed once the telescope is back online.
GMOS can perform broad band imaging (using the SDSS filter system) or narrow-band imaging using selected filters. The field of view is 5.5 arcmin x 5.5 arcmin (and does not cover the entire CCD package).
The GMOS-S original EEV CCDs, GMOS-N original EEV CCDs, and upgraded GMOS-N e2v DD devices had two ~ 2.8 arcsec (39 pixel)-wide chip gaps, as shown in the image below. To cover the gaps it is recommended to use dither steps of at least 5 arcsec in the X-direction.
On the new Hamamatsu CCDs at GMOS-S the two gaps are 4.88 arcsec wide (61 pixels in unbinned mode). The inter-chip gaps for the GMOS-N Hamamatsu CCDs are 5.4 arcsec wide (67 pixels in unbinned mode). Due to bright edges at either side of the chip gaps, it is recommended to use dither steps of 10 arcsec in the X-direction to cover the gaps of the GMOS-S and GMOS-N Hamamatsu CCDs.