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
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