Figure 2.
Snow clearing after winter
storm at Cerro Pachón.
cane season generated more than 10 named
storms to date. Thankfully there have been no
direct hits, but significant side effects have included long periods of fog and precipitation
at the summit, not to mention a fairly continual stream of flash flood warnings at sea level.
Hawaii’s hurricane season generally lasts until
the end of November, and we can only hope
it quiets down significantly before then.
In August, severe winter
weather at Cerro Pachón
deposited large amounts
of snow and ice on the
summit, forcing an evacuation; as a precaution,
Gemini South switched
to generator power that
day. After several more
days of bad weather, copious amounts of snow
continued to accumulate
on the access roads and
the summit itself.
When the storms abated, hard work by AURA
Shared Services cleared
the roads and allowed
observers and crew to
get back to the telescope
after a week. By that time, however, almost
all of the observatory’s fuel had been consumed; and without the possibility of getting a fuel truck
to the site, there was no alternative but to completely shutdown all systems.
Figure 3.
Rehearsal for the Gemini
South M1 recoating:
Preparing to lift the
dummy mirror.
23
generator power for over nine days, consuming almost 15,000 liters of diesel fuel. The following week, with assistance of the grader
and motor digger, a fuel truck made it to the
site, all systems were restarted, and normal
operations resumed.
All in all, Gemini South was closed for more
than two weeks, a rare occasion in recent
times and not good for our observing statistics. However, the great amounts of snow
melt water did a lot of good for the region,
and despite some local damage, was gratefully received.
Telescope Shutdowns
Both Gemini North and South telescopes
will be offline for maintenance shutdowns
during late September/mid-late October,
as this issue goes to e-press. At both sites, a
variety of maintenance tasks are scheduled,
with the biggest single task being the M1
(primary mirror) recoating at Gemini South;
in the north, the M2 (secondary mirror) will
be recoated. Numerous preparations, documentation revisions, and rehearsals have occurred in anticipation of the Gemini South
event, and the team is ready to safely and
successfully complete this delicate and complex primary mirror coating process. Particular attention has been given to a collabora-
Excellent teamwork between
the engineering groups allowed for a quick and safe
switch off of all equipment.
Last to be shut down was, of
course, the generator, with just
10 hours of fuel remaining! In
total, the observatory ran on
GeminiFocus
October 2015