made more transparent and user friendly. A
series of internal consistency checks minimizes the number of submitted faulty mask
designs, and a comprehensive user manual is
available. All in all, this amounts to a significant overhaul for GMMPS, making it a more
effective and user-friendly tool for mask creation (Figures 13-14).
holes. The power spectrum image shows
fringe power at 45 individual baselines;
these correspond to each pair of holes in
the mask and reveal the surprising degree
of inherent order in the image.
Data Center Re-engineering
Relatively unseen by the outside user, the
summit data centers have been re-engineered over the past six months. The new
data centers are split into hot and cold
zones, producing significant energy savings. They also foster greater sustainability
and cybersecurity.
Destructive Weather Event
in Chile
Figure 15.
GPI NRM “snowflakes”
observed during the
commissioning time
in May 2015. Left: Raw
data frame. Right:
Power spectrum.
Non-redundant Masking
with GPI
Commissioning of the Gemini Planet Imager (GPI) Non-Redundant Mask (NRM)
mode was scheduled for late March, and
coincided with the horrendous flooding
event described at right. Because of this,
no data were taken. Since this mode was
to produce some of the highest-contrast
observations with GPI, we rescheduled a
commissioning night in May. The team,
led by Peter Tuthill and Alexandra Greenbaum, visited the telescope and obtained a
night’s worth of useful data, which they are
now working to reduce.
Future users will need to become familiar
with the “snowflake” patterns produced
when the seeing is good and the NRM
mask is in place; two samples of this effect
appear in Figure 15.
For the technically inclined, the raw image
taken through the mask can be thought of
as an interferogram — a pattern formed
from fringes containing high spatial resolution; these cross the Airy disk diffraction
pattern caused by the individual circular
44
GeminiFocus
Near the end of March, Chile suffered a freak
storm that dumped many inches of rain on
the high deserts and caused major flooding
and destruction right down to the coast. Cerro Pachón was one of the affected areas. As
a result, Gemini South lost power, communications, and nights of telescope time. Thanks
to the quick and effective work by the engineering staff, the telescope was back on line
very shortly after the storm passed.
Washing the Gemini South
Primary Mirror
A few times annually, the Gemini South primary mirror is subjected to an in situ wash
in which the mirror, left in place on the telescope, is cleansed with specialized detergents
to remove dust particles. The latest wash occurred in April; we show a picture of the process here (Figure 16). An in situ wash requires
that we very carefully seal the bottom end of
the telescope so that the instruments, science
fold mirror, etc. do not get wet.
If you’re wondering whether we do this in
Hawai‘i also, the answer is no, and it’s because
of geology. The wind-blown dust on Cerro
2015 Year in Review
January 2016