it from responding correctly, was fixed. The
mirror is now working fine. The science-fold
mirror was also tuned for correct movement
between all the different focal stations, and
measurements were taken to consider the
feasibility of purchasing a spare.
Gemini Planet Imager
Commissioning Run
The fourth and final planned commissioning run for the Gemini Planet Imager (GPI)
was successfully completed during the first
half of September. Extensive testing in the
lab and on the flexure rig — to fully stress
test the instrument — preceded the commissioning run, as there has been extensive
work in both software and hardware. The
hardware changes address heating issues
in the electronics cabinet and also that with
vibrations from both the telescope structure
and the robust electronics within the imager
itself. Software updates focused on improving instrument performance and allowing a
smooth transition from commissioning into
science operations.
The latest commissioning run had several
major goals: to stress test the instrument’s
science operation integration; to dampen
vibrations by modifying the adaptive optics
control loops; to ameliorate the effects of vibration on the science images; to estimate
the contrast on various targets under the offered conditions in the queue; and to evaluate the effect of the improvements since the
last commissioning run. GPI is now being offered in 2014B.
GMOS Back for Science at
Gemini South
The Gemini Multi-Object Spectrograph
(GMOS) is back at work for imaging, taking science data with the new Hamamatsu
CCDs. As expected, the Hamamatsu CCDs
are significantly more sensitive in the red,
January 2015
and appear to perform as advertised from
the delivered QE curves pending final spectral throughput analysis. The new CCDs
have also greatly reduced fringing, being
now about 2 to 3 percent at 900 nanometers (compared to ~ 65 percent for the previous detectors).
As you might recall, a decision was made in
late 2012 to upgrade the GMOS-South detectors with the newly developed highly-sensitive CCDs manufactured by Hamamatsu Photonics. After an extensive period of testing in
Hilo, the new detector array was shipped to
Chile last April and installed in late May. The
array then underwent commissioning during
the following two months — including solving some electronics issues on the controllers.
Figure 4.
Images from GMOS,
showing a direct
comparison between
i’-band imaging of the
same field (E2V on the
left, Hamamatsu on the
right). These are raw,
unprocessed images,
which show how the
Hamamatsu CCDs
greatly reduce fringing.
As of the start of Semester 2014B, the new
CCDs are operating at full capacity. The
screenshot (Figure 4) shows a direct comparison between i’-band imaging of the same
field (previous E2V detector on the left, Hamamatsu on the right). These raw, unprocessed
images, should help you to appreciate the
new CCDs’ great reduction in fringing.
FLAMINGOS-2 Observations Start
Observations for 2014B programs with FLAMINGOS-2 (F-2) have started, with a healthy
distribution of 12 progr