components are integrated and undergoing
testing in Chicago at this time; the pre-ship
acceptance test is scheduled for late Octo-
ber. The plan is to commission the Front End
on the telescope first, using a simple detec-
tor, so that we are ready to commission the
MAROON-X spectrograph when it arrives
next year.
TOPTICA Laser Update
As a proven, stable laser platform, the new
TOPTICA fiber laser is expected to bring
more power and stability to Gemini North
(GN) laser operations. We continue to make
progress with the installation of the system.
With the old Lockheed Martin Coherent
Technologies laser removed and telescope
restored, we were able to begin modifying
the telescope to accept the new laser
and, in June, we began preparations
to install it.
ing logistically and required
careful planning.
The addition of new equip-
ment high on the telescope
required additional coun-
terbalance weights for the
telescope. These weights were designed
and added in sequence; doing so allowed
us to install the laser components (GNEST
and EC) while maintaining telescope bal-
ance through the day (July 19th). We then
installed the utilities and services for the
laser. Testing began with power on August
16th, followed by first open-beam verifica-
tion on the 22nd. Laser alignment through
the optical path to the Beam Transfer Op-
tics Optical Bench on the secondary was
verified, allowing us to conduct our first on-
sky propagation at zenith on August 31st.
Gemini Optical Engineer
Tom Schneider prepares
insulation for GNEST (laser
housing designed for our
TOPTICA laser head and
optical bench).
Figure 7 (above center).
Gemini senior optical
technician Clayton Ah
Hee (left, in foreground)
and Gemini summit
crew member John
Randrup prepare GNEST
for installation onto
telescope.
Figure 8 (above right).
Verifying laser alignment
through the optical path
to the Beam Transfer
Optics Optical Bench on
the secondary.
The GN laser design allowed the cre-
ation of a single housing for both the
laser head and Beam Injection Module
Optical Bench. We refer to the housing
as GNEST (Gemini North Enclosure Sys-
tem for TOPTICA). The laser head with-
in the GNEST is coupled to the TOPTI-
CA Electronics Cabinet (EC) by optical
fibers and communication cabling. We
maintained the fiber coupling during
installation, which was quite demand-
October 2018
Figure 6 (above left).
Figure 9 (bottom
right).
Installing GNEST onto
telescope truss below
top ring.
Credit: All photos this
page by Jeff Donahue
GeminiFocus
19