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Status and Availability

On-going development projects concerning GeMS are (in June 2015):

  • an upgrade of the NGS wavefront sensor. The new project called NGS2, lead by our partner at ANU, will push the magnitude limit up to 17 (goal: 17.5), dramatically improving the GeMS sky coverage as well as its performances. (Expected delivery and commissioning in 2016).
  • a replacement of the current laser for a more robust laser.
  • a package of many small to medium-sized improvements to streamline/automatize operations and reduce overheads.
  • preparing GeMS for other Gemini-S instruments...

GeMS/GSAOI combination is now in regular operation (2013B).

The GSAOI IR On-Detector Guide Window (ODGW) use has been found superfluous in most science cases as the flexure between the Canopus MCAO bench and the GSAOI instrument is relatively small. We currently deliver AO correction using from 1 to 3 natural guide stars (NGS) with the 3 visible pyramids guide probes. The uniformity of the PSF across the GSAOI Field of View increases with the number of NGS used (please consult the following page for more informations).

GeMS will be in commissioning / Science Verification in 2012.

We anticipate announcing the call for System Verification (SV) proposals to use the Gemini Multi-Conjugate Adaptive Optics System (GeMS) with the Gemini South Adaptive Optics Imager (GSAOI) the last week of August. The observations are likely to be executed in December 2012 and January 2013. More information will be provided here.


Two modes of operations will be offered with GeMS. The first mode (called 3+1), uses the 3 visible pyramid probes described above combined with 1 OI star to correct for flexure. The second mode is specific to GSAOI, as this instrument can also provide a fast Tip-Tilt guiding capability. This is based on an On-Detector Guide Window (ODGWs) technology (see here for more details). The ODGWs are used in a fast readout mode, providing the Tip-Tilt information based on the centroid position of the stars. In this mode, one visible star (one of the three probes) is still needed for slow focus compensation. This mode is called 1+3, i.e., one visible focus NGS and three fast near-infrared Tip-Tilt NGSs. Only the 3+1 mode will be offered during SV and the first period of operations.