The Gattini South Pole UV experiment (Gattini SPUV) was deployed to the South Pole dark sector in February 2010 and
has recently completed a highly successful first season of winter time observations. The experiment has, for the first time
ever, measured and categorized the optical night sky brightness at the very blue wavelengths. The experiment consists of
a remotely operated 6” aperture custom designed telescope. The telescope feeds a blue sensitive imager with 4 degree
field of view that contains a bank of 3 filters: SDSS g’, Bessel U and a custom “super U” filter specifically designed to
probe the sky emission at wavelengths approaching the atmospheric cut-off. The filters are continually cycled with
exposure times ranging from 30 to 300 seconds throughout the winter period. The telescope, in addition, feeds a 2 degree
long slit VPH grating spectrograph with R~1000. The bandwidth is 350-450nm. The spectra are recorded simultaneously
with the imager exposures. The experiment is designed for low temperature Antarctic operation and resides on the roof
of the MAPO building in the South Pole Antarctic sector. The primary science goals are to categorize the Antarctic
winter-time sky background at the very bluest of wavelengths as a pathfinder for the Antarctic Cosmic Web Imager. We
present a technical overview of the experiment and results from the first winter season.
We report on the preliminary design of W.M. Keck Observatory's (WMKO's) next-generation adaptive optics (NGAO)
facility. This facility is designed to address key science questions including understanding the formation and evolution
of today's galaxies, measuring dark matter in our galaxy and beyond, testing the theory of general relativity in the
Galactic Center, understanding the formation of planetary systems around nearby stars, and exploring the origins of our
own solar system. The requirements derived from these science questions have resulted in NGAO being designed to
have near diffraction-limited performance in the near-IR (K-Strehl ~ 80%) over narrow fields (< 30" diameter) with
modest correction down to ~ 700 nm, high sky coverage, improved sensitivity and contrast and improved photometric
and astrometric accuracy. The resultant key design features include multi-laser tomography to measure the wavefront
and correct for the cone effect, open loop AO-corrected near-IR
tip-tilt sensors with MEMS deformable mirrors (DMs)
for high sky coverage, a high order MEMS DM for the correction of atmospheric and telescope static errors to support
high Strehls and high contrast companion sensitivity, point spread function (PSF) calibration to benefit quantitative
astronomy, a cooled science path to reduce thermal background, and a high-efficiency science instrument providing
imaging and integral field spectroscopy.
The Palomar Transient Factory (PTF) is a new fully-automated, wide-field survey conducting a systematic exploration
of the optical transient sky. The transient survey is performed using a new 8.1 square degree, 101 megapixel camera
installed on the 48-inch Samuel Oschin Telescope at Palomar Observatory. The PTF Camera achieved first light at the
end of 2008, completed commissioning in July 2009, and is now in routine science operations. The camera is based on
the CFH12K camera, and was extensively modified for use on the 48-inch telescope. A field-flattening curved window
was installed, the cooling system was re-engineered and upgraded to closed-cycle, custom shutter and filter exchanger
mechanisms were added, new custom control software was written, and many other modifications were made. We here
describe the performance of these new systems during the first year of Palomar Transient Factory operations, including
a detailed and long term on-sky performance characterization. We also describe lessons learned during the construction
and commissioning of the upgraded camera, the photometric and astrometric precision currently achieved with the PTF
camera, and briefly summarize the first supernova results from the PTF survey.
W. M. Keck Observatory (WMKO) is currently engaged in the design of a powerful new Adaptive Optics (AO) science
capability providing precision correction in the near-IR, good correction in the visible, and faint object multiplexed
integral field spectroscopy. Improved sensitivity will result from significantly higher Strehl ratios over narrow fields (<
30" diameter) and from lower backgrounds. Quantitative astronomy will benefit from improved PSF stability and
knowledge. Strehl ratios of 15 to 25% are expected at wavelengths as short as 750 nm. A multi-object AO approach
will be taken for the correction of multiple science targets over modest fields of regard (< 2' diameter) and to achieve
high sky coverage using AO compensated near-IR tip/tilt sensing. In this paper we present the conceptual design for this
system including discussion of the requirements, system architecture, key design features, performance predictions and
The Next Generation Adaptive Optics (NGAO) system will represent a considerable advancement for high resolution
astronomical imaging and spectroscopy at the W. M. Keck Observatory. The AO system will incorporate multiple laser
guidestar tomography to increase the corrected field of view and remove the cone effect inherent to single laser guide
star systems. The improvement will permit higher Strehl correction in the near-infrared and diffraction-limited correction
down to R band. A high actuator count micro-electromechanical system (MEMS) deformable mirror will provide the
on-axis wavefront correction to a number of instrument stations and additional MEMS devices will feed multiple
channels of a deployable integral-field spectrograph. In this paper we present the status of the AO system design and
describe its various operating modes.
We present a concept to perform low-order wavefront sensing in multi-laser guide star adaptive optics systems
operating using a large format NIR detector with windowing capability with near diffraction limited or partially
corrected NGS tip-tilt stars with time varying Strehls. Most contemporary adaptive optics systems in development
for large telescopes, viz., the next VLT adaptive optics facility that serves as a pathfinder to the European
ELT, Gemini MCAO, W. M. Keck observatory's Next Generation Adaptive Optics (NGAO) System, The Large
Binocular Telescope and the Thirty Meter Telescope's NFIRAOS are multi-laser guide star systems that provide
AO correction over a large field. In such systems even faint tip-tilt (TT) stars image are characterized by either
a well corrected (MOAO case) or at least a partially corrected (MCAO or GLAO case) diffraction limited core
due to high order sharpening by the LGS WFS. In such a regime of low-order sensing one could envisage using
pixels as field stops and choosing a appropriate plate scale to minimize the sky background.
Simulations are used to predict the performance of such a sensor when guiding on point sources and on
extended objects of varying brightness and for different levels of high order correction.
The parameter space explored includes tip-tilt and tip-tilt, focus and astigmatism (TTFA) sensor performance
for various plate scales, TT sensor performance vs. level of high order correction (TT star Strehl) and TT sensor
performance vs. TT object size for a given detector noise, gain and a simple centroiding algorithm. Due to small
sky noise contribution at plate-scales le 100 mas/pixel, the optimum low-order wavefront sensor plate scale is
found to be 80-100 mas/pixel (3×-4× λ/d in J- and H- bands) for the Keck NGAO system.
The Palomar Transient Factory is an automated wide-field survey facility dedicated to identifying a wide range of
transient phenomena. Typically, a new 7.5 square degree field will be acquired every 90 seconds with 66% observing
efficiency, in g' band when the sky is dark, or in R band when the moon is up. An imaging camera with a 12Kx8K
mosaic of MIT/LL CCDs, acquired from CFHT, is being repackaged to fit in the prime focus mounting hub of the
Palomar 48-inch Oschin Schmidt Telescope. We discuss how we have addressed the broad range of issues presented by
this application: faster CCD readout to improve observing efficiency, a new cooling system to fit within the constrained
space, a low impact shutter to maintain reliability at the fast observing cadence, a new filter exchange mechanism, and
the field flattener needed to correct for focal plane curvature. The most critical issue was the tight focal plane alignment
and co-planarity requirements created by the fast beam and coarse plate scale. We built an optical profilometer system to
measure CCDs heights and tilts with 1 μm RMS accuracy.
We describe the work that has gone into taking the sodium Laser Guide Star (LGS) program on the Palomar AO system
from a successful experiment to a facility instrument. In particular, we describe the operation of the system, the BTO
(beam transfer optics) system which controls the path of the laser in the dome, the aircraft safety systems and the optical
systems which allow us to take advantage of the unique properties of the macro/micro pulse laser. In addition we
present on sky performance results that demonstrate K-band Strehl ratios of up to 48%
We have recently demonstrated diffraction-limited resolution imaging in the visible on the 5m Palomar Hale telescope.
The new LAMP instrument is a Lucky Imaging backend camera for the Palomar AO system. Typical resolutions of
35-40 mas with Strehls of 10-20% were achieved at 700nm, and at 500nm the FWHM resolution was as small as 42
milliarcseconds. In this paper we discuss the capabilities and design challenges of such a system used with current and
near future AO systems on a variety of telescopes. In particular, we describe the designs of two planned Lucky Imaging
+ AO instruments: a facility instrument for the Palomar 200" AO system and its PALM3K upgrade, and a visible-light
imager for the CAMERA low-cost LGS AO system planned for the Palomar 60" telescope. We introduce a Monte Carlo
simulation setup that reproduces the observed PSF variability behind an adaptive optics system, and apply it to predict the
performance of 888Cam and CAMERA. CAMERA is predicted to achieve diffraction-limited resolution at wavelengths as
short as 350 nm. In addition to on-axis resolution improvements we discuss the results of frame selection with the aim of
improving other image parameters such as isoplanatic patch sizes, showing that useful improvements in image quality can
be made by Lucky+AO even with very temporally and spatially undersampled data.
Deployed as a multi-user shared facility on the 5.1 meter Hale Telescope at Palomar Observatory, the PALM-3000 highorder
upgrade to the successful Palomar Adaptive Optics System will deliver extreme AO correction in the near-infrared,
and diffraction-limited images down to visible wavelengths, using both natural and sodium laser guide stars. Wavefront
control will be provided by two deformable mirrors, a 3368 active actuator woofer and 349 active actuator tweeter,
controlled at up to 3 kHz using an innovative wavefront processor based on a cluster of 17 graphics processing units. A
Shack-Hartmann wavefront sensor with selectable pupil sampling will provide high-order wavefront sensing, while an
infrared tip/tilt sensor and visible truth wavefront sensor will provide low-order LGS control. Four back-end instruments
are planned at first light: the PHARO near-infrared camera/spectrograph, the SWIFT visible light integral field
spectrograph, Project 1640, a near-infrared coronagraphic integral field spectrograph, and 888Cam, a high-resolution
visible light imager.
CAMERA is an autonomous laser guide star adaptive optics system designed for small aperture telescopes.
This system is intended to be mounted permanently on such a telescope to provide large
amounts of flexibly scheduled observing time, delivering high angular resolution imagery in the visible
and near infrared. The design employs a Shack Hartmann wavefront sensor, a 12x12 actuator MEMS
device for high order wavefront compensation, and a solid state 355nm ND:YAG laser to generate a
guide star. Commercial CCD and InGaAs detectors provide coverage in the visible and near infrared.
CAMERA operates by selecting targets from a queue populated by users and executing these observations
autonomously. This robotic system is targeted towards applications that are diffcult to address
using classical observing strategies: surveys of very large target lists, recurrently scheduled observations,
and rapid response followup of transient objects. This system has been designed and costed, and
a lab testbed has been developed to evaluate key components and validate autonomous operations.
The Gemini/Subaru WFMOS project has given the stimulus for considering new concepts for massively multiplexed
fiber positioning schemes. The problem of acquiring many thousands of objects within a ~1.5° field at Subaru's ~f/2
prime-focus station represents a challenge to normal concepts of fiber positioning. Solutions usually involve imposing
limits to the patrol field of each fiber. Using this simplification, a new concept is proposed which moves objects onto a
fixed array of fibers rather than moving the fiber themselves. Such a scheme may simplify the manufacturing and
assembly processes and may result in a more robust solution compatible with the challenging prime-focus environment.
We describe the POSM concept and present an initial opto-mechanical layout.
PALM-3000 is proposed to be the first visible-light sodium laser guide star astronomical adaptive optics system. Deployed as a multi-user shared facility on the 5.1 meter Hale Telescope at Palomar Mountain, this state-of-the-art upgrade to the successful Palomar Adaptive Optics System will have the unique capability to open the visible light spectrum to diffraction-limited scientific access from the ground, providing angular imaging resolution as fine as 16 milliarcsec with modest sky coverage fraction.
We have built and field tested a multiple guide star tomograph with four Shack-Hartmann wavefront sensors. We predict the wavefront on the fourth sensor channel estimated using wavefront information from the other three channels using synchronously recorded data. This system helps in the design of wavefront sensors for future extremely large telescopes that will use multi conjugate adaptive optics and multi object adaptive optics. Different wavefront prediction algorithms are being tested with the data obtained. We describe the system, its current capabilities and some preliminary results.
Work is underway at the University of Chicago and Caltech Optical Observatories to implement a sodium laser guide star adaptive optics system for the 200 inch Hale telescope at Palomar Observatory. The Chicago sum frequency laser (CSFL) consists of two pulsed, diode-pumped, mode-locked Nd:YAG lasers working at 1.064 micron and 1.32 micron wavelengths. Light from the two laser beams is mixed in a non-linear crystal to produce radiation centered at 589 nm with a spectral width of 1.0 GHz (FWHM) to match that of the Sodium-D2 line. Currently the 1.064 micron and 1.32 micron lasers produce 14 watts and 8 watts of TEM-00 power respectively. The laser runs at 500 Hz rep. rate with 10% duty cycle. This pulse format is similar to that of the MIT-Lincoln labs and allows range gating of unwanted Rayleigh scatter down an angle of 60 degrees to zenith angle. The laser system will be kept in the Coude lab and will be projected up to a laser launch telescope (LLT) bore-sited to the Hale telescope. The beam-transfer optics, which conveys the laser beam from the Coude lab to the LLT, consists of motorized mirrors that are controlled in real time using quad-cell positioning systems. This needs to be done to prevent laser beam wander due to deflections of the telescope while tracking. There is a central computer that monitors the laser beam propagation up to the LLT, the interlocks and safety system status, laser status and actively controls the motorized mirrors. We plan to install a wide-field visible camera (for high flying aircraft) and a narrow field of view (FoV) IR camera (for low-flying aircraft) as part of our aircraft avoidance system.