GeminiFocus October 2016 | Page 13

Field Spectrometer (NIFS); it is also being offered in shared-risk mode with the Gemini Near-InfraRed Spectrometer (GNIRS). It is important to understand that significant flexure issues remain, which limit the use of LGS + P1 on targets that are not visible during acquisition; this mode also significantly limits the amount of time that a target can remain in a spectroscopic slit. In fact, for spectroscopy, the Super Seeing mode requires that a continuum source be visible (signal-to-noise ratio > 1 per spectral element) somewhere in the science frame for typical exposure times (~ 15 minutes). In addition, we cannot support blind offsetting at this time. Since this is a work-in-progress, part of the mode’s shared risk nature includes the possibility that we may not be able to implement the flexure model, or that the magnitude of flexure may be larger or more difficult to correct than expected. ter and initiate an unplanned shutdown to work on the lower shutter, as well as perform work that was originally scheduled for a planned shutdown in October. That work included troubleshooting on the Acquisition and Guiding system, maintenance on the Gemini Multi-Object Spectrograph (GMOS), and a filter exchange on the Near-InfraRed Imager (NIRI). Thanks to this solution we plan to be observing on a normal schedule throughout October. A GRACES run had been scheduled during the unplanned August shutdown, but an agreement with the Canada-France-Hawai‘i Telescope allowed us to continue with these programs following the shutdown. — Andy Adamson and Steve Hardash Figure 2. Hoisting a 150-pound drive motor, using one of the largest cranes available on the island of Hawai‘i. Nevertheless the Super Seeing mode has proven to be very useful for conventional LGS mode programs for which the availability of guide stars was an issue; in about 99% of the cases, the Super Seeing mode was there to help by reducing the natural seeing PSF FWHM by at least a factor of two. — Marie Lemoine-Busserolle Gemini North Shutdown Figure 3. Gemini North had an unscheduled shutdown from August 10-31 to remedy a broken bearing in one of the drive boxes on the lower shutter (which is also responsible for de ploying the wind blind during high wind conditions). This drive box failed in late July, resulting in the lower shutter being pinned in an inconveniently high position until a shutdown was possible. Favorable observing conditions near the end of 2016A allowed us to do a significant amount of 2016B observing before the semester started. This then allowed us to take advantage of a relatively light queue at this early stage in the semes- October 2016 The Gemini North bottom shutter’s broken drive box, with a segment of the drive chain showing at left. GeminiFocus 11