The University of California (UC) began operating the Lick Observatory onMount Hamilton, California in 1888. Nearly a
century later, UC became a founding partner in the establishment of theW. M. Keck Observatory (WMKO) in Hawaii, and
it is now a founding partner in the Thirty Meter Telescope (TMT) project. Currently, most UC-affiliated observers conduct
the majority of their ground-based observations using either the Keck 10-meter Telescopes on Mauna Kea or one or more
of the six Lick telescopes now in operation on Mount Hamilton; some use both the Keck and Lick Telescopes. Within the
next decade, these observers should also have the option of observing with the TMT if construction proceeds on schedule.
During the current decade, a growing fraction of the observations on both the Keck and Lick Telescopes have been
conducted from remote observing facilities located at the observer's home institution; we anticipate that TMT observers
will expect the same. Such facilities are now operational at 8 of the 10 campuses of UC and at the UC-operated Lawrence
Berkeley National Laboratory (LBNL); similar facilities are also operational at several other Keck-affiliated institutions.
All of the UC-operated remote observing facilities are currently dual-use, supporting remote observations with either the
Keck or Lick Telescopes.
We report on our first three years of operating such dual-use facilities and describe the similarities and differences
between the Keck and Lick remote observing procedures. We also examine scheduling issues and explore the possibility
of extending these facilities to support TMT observations.
At the University of California's Lick Observatory, we have implemented an on-sky testbed for next-generation
adaptive optics (AO) technologies. The Visible-Light Laser Guidestar Experiments instrument (ViLLaGEs)
includes visible-light AO, a micro-electro-mechanical-systems (MEMS) deformable mirror, and open-loop control
of said MEMS on the 1-meter Nickel telescope at Mt. Hamilton. (Open-loop in this sense refers to the MEMS
being separated optically from the wavefront sensing path; the MEMS is still included in the control loop.) Future
upgrades include predictive control with wind estimation and pyramid wavefront sensing. Our unique optical
layout allows the wavefronts along the open- and closed-loop paths to be measured simultaneously, facilitating
comparison between the two control methods. In this paper we evaluate the performance of ViLLaGEs in openand
closed-loop control, finding that both control methods give equivalent Strehl ratios of up to ~ 7% in I-band
and similar rejection of temporal power. Therefore, we find that open-loop control of MEMS on-sky is as effective
as closed-loop control. Furthermore, after operating the system for three years, we find MEMS technology to
function well in the observatory environment. We construct an error budget for the system, accounting for 130
nm of wavefront error out of 190 nm error in the science-camera PSFs. We find that the dominant known term
is internal static error, and that the known contributions to the error budget from open-loop control (MEMS
model, position repeatability, hysteresis, and WFS linearity) are negligible.
Visible Light Laser Guidestar Experiments (ViLLaGEs) is a new Micro-Electro Mechanical Systems (MEMS)
based visible-wavelength adaptive optics (AO) testbed on the Nickel 1-meter telescope at Lick Observatory. Closed
loop Natural Guide Star (NGS) experiments were successfully carried out during engineering during the fall of
2007. This is a major evolutionary step, signaling the movement of AO technologies into visible light with a MEMS
mirror. With on-sky Strehls in I-band of greater than 20% during second light tests, the science possibilities have
become evident.
Described here is the advanced engineering used in the design and construction of the ViLLaGEs system, comparing
it to the LickAO infrared system, and a discussion of Nickel dome infrastructural improvements necessary for this
system. A significant portion of the engineering discussion revolves around the sizable effort that went towards
eliminating flexure. Then, we detail upgrades to ViLLaGEs to make it a facility class instrument. These upgrades
will focus on Nyquist sampling the diffraction limited point spread function during open loop operations,
motorization and automation for technician level alignments, adding dithering capabilities and changes for near
infrared science.
We attempt to linearize the output of the Shack-Hartmann wavefront sensor in the ViLLaGEs instrument. ViLLaGEs
(Visible Light Laser Guidestar Experiments) is a MEMS-based Adaptive Optics system on the 1 - meter Nickel
telescope at Lick Observatory meant to provide correction at visible wavelengths with a 9x9 subaperture Hartmann
sensor. We estimate that the open-loop accuracy of ViLLaGEs is ~40 nm. We "calibrate" the Hartmann linearity by
raster scanning a tip/tilt mirror downstream of an internal fiber and inverting the resulting signal, forming a lookup table
of unbiased tilts. From this calibration, we conclude that nonlinearity is a minor effect in the open-loop operation of
ViLLaGEs, on the order of ~15 nm. We show through simulations of Shack-Hartmann sensors that this error is likely
due to an internal pupil mask not physically conjugate to the telescope pupil. We test the resulting lookup table on an
internal "turbulator" in ViLLaGEs, or a rotating plate meant to simulate the wind-driven atmosphere, and find that the
Strehls with and without the lookup table are indistinguishable.
We describe a project to enable remote observing on the Nickel 1-meter Telescope at Lick Observatory. The purpose
was to increase the subscription rate and create more economical means for graduate- and undergraduate students to
observe with this telescope. The Nickel Telescope resides in a 125 year old dome on Mount Hamilton. Remote
observers may work from any of the University of California (UC) remote observing facilities that have been created to
support remote work at both Keck Observatory and Lick Observatory.
The project included hardware and software upgrades to enable computer control of all equipment that must be operated
by the astronomer; a remote observing architecture that is closely modeled on UCO/Lick's work to implement remote
observing between UC campuses and Keck Observatory; new policies to ensure safety of Observatory staff and
equipment, while ensuring that the telescope subsystems would be suitably configured for remote use; and new software
to enforce the safety-related policies.
The results increased the subscription rate from a few nights per month to nearly full subscription, and has spurred the
installation of remote observing sites at more UC campuses. Thanks to the increased automation and computer control,
local observing has also benefitted and is more efficient. Remote observing is now being implemented for the Shane 3-
meter telescope.
The Lick Observatory is pursuing new technologies for adaptive optics that will enable feasible low cost laser guidestar
systems for visible wavelength astronomy. The Villages system, commissioned at the 40 inch Nickel Telescope this past
Fall, serves as an on-sky testbed for new deformable mirror technology (high-actuator count MEMS devices), open-loop
wavefront sensing and control, pyramid wavefront sensing, and laser uplink correction. We describe the goals of our
experiments and present the early on-sky results of AO closed-loop and open-loop operation. We will also report on our
plans for on-sky tests of the direct-phase measuring pyramid-lenslet wavefront sensor and plans for installing a laser
guidestar system.
The MEMS-AO/Villages project consists of a series of on-sky experiments that will demonstrate key new
technologies for the next generation of adaptive optics systems for large telescopes. One of our first goals is to
demonstrate the use of a micro-electro-mechanical systems (MEMS) deformable mirror as the wavefront correcting
element. The system is mounted the 1-meter Nickel Telescope at the UCO/Lick Observatory on Mount Hamilton. It
uses a 140 element (10 subapertures across) MEMS deformable mirror and is designed to produce diffraction-limited
images at wavelengths from 0.5 to 1.0 microns. The system had first light on the telescope in October 2007.
Here we report on the results of initial on-sky tests.
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