July 2014
FLAMINGOS-2 Developments
Although FLAMINGOS-2 (F-2) was successfully recommissioned in late 2013, the optical system had significant problems. An
intensive series of consultations, modeling,
and investigations determined that the
problem was an inverted lens in the camera
barrel. This required removal from the telescope and remedial work in April 2014. The
problem was rectified in this work, and the
instrument has returned to the telescope.
The image quality is now excellent across
the entire field-of-view (Figure 8).
Spectroscopic performance has benefited
somewhat from the change, but spectral
resolution away from the center remains
well outside of specification. Further modeling is required to determine how to return
the instrument to optimum performance —
as demonstrated earlier during commissioning tests.
See updates in October 2014 (p. 37) and January
2015 (p. 34).
GeMS Laser
The GeMS laser, specified for 50 Watts (W),
has experienced significant issues and in
early 2014 its power output deteriorated to
20 - 30W. Nevertheless, GeMS operations proceeded with scheduled runs
in April, May, and June (Figure 9). Serendipity played a role in these runs;
the return of a seasonally strong sodium layer enabled us to obtain some
good data for Principal Investigator
programs. With winter now in full
swing in the Southern Hemisphere
GeMS will return to the lab, and work
will continue on returning the laser to
a higher power level, which will surely be needed for consistent science
returns in the next southern summer
when sodium returns are lower.
January 2015
GMOS CCDs
Figure 8.
The new focal plane for the Gemini Multi-Object Spectrograph at Gemini South (GMOS-S)
— equipped with three red-sensitive Hamamatsu CCDs — was shipped to Chile early in
2014. The instrument team then carried out
intensive “burn-in” testing in the lab before
installing it into GMOS-S. GMOS returned to
the telescope two weeks ahead of schedule,
and on-sky tests are currently underway as
illustrated in Figure 10. Images and spectra
taken with these new detectors may appear
by the time the next issue of GeminiFocus
goes to press.
2014 Year in Review
GeminiFocus
Point-spread-function
plot of F-2 imaging
as measured relative
to the center of the
optical axis before
(blue) and after
(orange) reversal of
lens mentioned in text.
Figure 9.
Gemini South laser
propagates into the sky
over Cerro
Pachón.
Despite lower
power, many
programs were
successfully
fulfilled due to
the seasonal
variations
in the
atmospheric
sodium
layer which
provided
stronger guide
star returns.
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