is scheduled to reach completion in April
2013. Next, the instrument will be shipped
to Gemini South for on-site acceptance testing in May-June 2013. Verification and commissioning is scheduled to start in August
2013 with the science campaign beginning
in late 2013B.
The GPI’s Integral Field Spectrograph has
now been successfully integrated with the
rest of the instruments, and the resulting remediation task list has been completed. We
are also starting to see very good contrast
ratios in the lab, as shown in Figure 3.
In late May, 2012, the primary deformable
mirror (DM) in GPI developed a sticky actuator which limited its motion. Luckily, the
new bad actuator is quite near a spider vane
in the Lyot masks, so we have now made and
installed new masks with a new extension
off one vane to block the offending actuator. Simulations show we will still be able to
achieve the desired science specifications
even with this bad actuator.
High-resolution Optical
Spectroscopy at Gemini:
GHOS and Graces
GHOS
As of this writing, we are starting the contract
approval process for the Post-Conceptual
Design Stage for GHOS, the future Gemini
High-resolution Optical Spectrograph. This
December2012
contract will see us through the Preliminary
and Critical Design stages as well as the Build
and Integration and Testing work. Once approved by both key institutions (Gemini and
the build team), the contract needs to go to
the Association of Universities for Research
in Astronomy Board for approval, then on
to the National Science Foundation and the
team’s funding agencies for the final sign-off.
It is difficult to predict how long this approval
process will take, but we certainly expect to
be able to have more concrete details about
GHOS and the design/build team to share
with you in the next issue of GeminiFocus,
with a public announcement well before that.
GRACES
Since the previous GeminiFocus article, several fibers of different lengths and types have
been tested at HIA for throughput and focal
ratio degradation. Unfortunately, the results
were not consistent and we were unable to
make any conclusive statements about the
suitability of the fibers we are exploring for
the inter-telescope connection between
Gemini North and the Canada-France-Hawaii Telescope. As a result, the fiber has been
outsourced to a vendor who will completely
prepare the fiber ends and properly protect
and sheathe the cable before delivery. The
result should be the final fiber optic cable we
can install and use with GRACES. The vendor
is expected to deliver the fiber by the end of
2012, so we should have additional information soon. Given this switch to procuring
GeminiFocus
Figure 3.
Left: Contrast vs. radius
in closed-loop GPI
testing, with no external
aberrations. The light
source represents a
bright (H~3 magnitude)
star. Top blue curve
shows contrast with
WFS reference centroids
generated using an
optical fiber during final
alignment. The green
curve shows contrast
with WFS reference
centroids generated
immediately before the
exp