when the telescope points to different parts
of the sky. Next GPI went into a cold room
(See Figures 3 and 4) and exposed it to the
large range of temperatures that will occur
at Gemini South.
While being tilted at varying angles and
subjected to freezing temperatures, the
team took GPI through a large set of tests
and demonstrated to micrometer precision
that it was able to maintain its extremely
high contrast performance. As expected, GPI
passed these rigorous exams with bravura.
Once GPI is unpacked, at Cerro Pachón, it
will go through a subset of these rigorous
tests to assure that shipping the instrument
several thousand kilometers didn’t cause
any ill effects. Next, GPI will be mounted
onto the telescope at the beginning of the
fourth quarter of 2013. The instrument’s
much awaited first light will follow, which
should reveal the instrument’s amazing capabilities. Commissioning and Science Verification activities should then occupy GPI
for the rest of the year.
— Stephen Goodsell and Fredrik Rantakyro
GRACES Progress
The Gemini Remote Access to the CanadaFrance-Hawaii ESPaDOnS Spectrograph
(GRACES) project is entering the latter
stages of Phase I, the so-called “Experimental Phase,” which should demonstrate that
world-class, high-resolution spectroscopy
can be achieved using Gemini North to
feed ESPaDOnS.
GRACES is designed to have two resolutions: R=55,000 and 33,000, with a wavelength range of ~400 nanometers (nm)
to ~1000 nm. It also has two observing
modes: “Source+Sky” and “Source-only”
(the latter is intended for bright sources).
GRACES’ most critical component, however, is the 270-meter-long, optical-fiber cable, which must achieve high performance
— excellent focal-ratio degradation (RFD),
internal transmission, and spectral range
coverage — if it’s to compete with other 8to 10-meter-class, high-resolution spectrographs, such as the High Resolution Echelle
Spectrometer at Keck Observatory or the
Ultraviolet and Visual Echelle Spectrograph
at the Very Large Telescope.
Currently the GRACES project is advancing
on all fronts. The optical-fiber-cable vendor has overcome some earlier problems in
processing the fiber ends and is consistently producing 2-meter-long test fiber cables
with measured RFDs of about 5 percent.
This is a milestone event toward achieving
an RFD on the 270-meter-long science cable of ~20 percent (required) to ~10 percent
(goal); the cable is partially fabricated and
will be “connectorized,” armored, tested,
and delivered in July. We’ve received all of
the optics (e.g., lenses and slicer) and commercial hardware (e.g., translation stages,
adjusters, and mounts), and the custom
July2013
GeminiFocus
Figure 4:
Stephen Goodsell in front
of the cold room at the
University of California
Santa Cruz.
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