trol System maintenance. Additional work
planned includes enclosure bogie work and
enclosure bottom shutter work, which will
commence later in the shutdown.
Big Island Mechanical, the contractor install-
ing the Gemini North energy savings hard-
ware, worked together with Gemini day crew
to move the new Chiller 2 modules into the
Exhaust Tunnel and onto the vibration isola-
tion frame. Gemini is also temporarily shut-
ting down the Chiller 1 cooling water circuit
during the shutdown so that Big Island Me-
chanical can cut into the existing piping to
install new hardware.
JULY 2018
IGRINS Achieves First Light at
Gemini South
IGRINS, the visiting high-resolution near-
infrared spectrometer — a collaboration of
the University of Texas Austin (UT Austin)
and the Korea Astronomy and Space Sci-
ence Institute (KASI) — achieved first light
on the night of April 2nd at Gemini South,
with a remarkable spectrum of the T-Tauri
star TW Hydrae (Figure 12).
What’s unique about IGRINS is its revolu-
tionary combination of spectral coverage
(the entire H and K bands in a single expo-
sure), high spectral resolution (R = 45,000)
and high throughput (achieved through
January 2019 / 2018 Year in Review
the use of a silicon immersion grating). It is
also extremely compact and mechanically
simple — having a single observing mode
and no cryogenic moving parts. IGRINS
adapts easily to different telescopes, re-
quiring only a change of either fore-optics
or input optics; in the case of Gemini, the
input optics required replacement. IGRINS
and Gemini South offer the most powerful
combination yet.
Since installation, IGRINS has been perform-
ing exactly as expected; at its spectral reso-
lution (45,000), IGRINS’ sensitivity is about
seven times better than any other high-reso-
lution IR spectrometer on an 8- to 10-meter-
class telescope, and it has many times the
spectral coverage of other instruments at
that resolution. Not surprisingly, demand for
it at Gemini has been extremely high, with a
list of 21 approved programs from the Gem-
ini Participants, as well as a Large and Long
Program of the instrument team.
This is IGRINS’ first visit to the Southern
Hemisphere, and the results from our first
light target, TW Hydrae, is a good exam-
ple of how much latitude matters. When
IGRINS was running at McDonald Observa-
tory in the Northern Hemisphere, observers
worked hard for several years to obtain a
spectrum of TW Hydrae, which was always
very low in the Texas sky. With IGRINS at
Gemini South, however, TW Hya was right
overhead, and the first-light spectrum
was not only quickly and easily observed,
GeminiFocus
Figure 12.
IGRINS+Gemini South
first light.
Left:TW Hydrae in the
slit-viewing camera.
Center: the H-band
spectrum.
Right: the K-band
spectrum.
Credit: K. Sokal and the
IGRINS team
63