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Introduction
Full text linkThe large number of submissions to and excellent attendance at the Ground-based
and Airborne Telescopes IV conference reflects the strong and growing
interest in the astronomical and engineering communities. More than 250 papers
were submitted to this year's conference, the largest number in the series' history.
This year's conference included 28 oral sessions and two poster sessions
Site selection for Extremely Large Telescopes using the FriOWL software and global re-analysis climate data
No full textThe 4m international liquid mirror telescope (ILMT)
Full text linkThe entire funding has recently been obtained in Belgium for the construction of a 4m Liquid Mirror Telescope. Its prime focus will be equipped with a semi-conventional glass corrector allowing to correct for the TDI effect and a thinned, high quantum efficiency, 4K × 4K pixel equivalent CCD camera. It will be capable of subarcsecond imaging in the i'(760 nm) and possibly r', g' band(s) over a field of ~ 30' in diameter. This facility will be entirely dedicated to a deep photometric and astrometric variability survey over a period of ~ 5 years. In this paper, the working principle of liquid mirror telescopes is first recalled, along with the advantages and disadvantages of the latter over classical telescopes. Several science cases are described. For a good access to one of the galactic poles, the best image quality sites for the ILMT are located either in Northern Chile (latitude near -29°30') or in North-East India (Nainital Hills, latitude near +29°30'). At those geographic latitudes, a deep (i' = 22.5 mag.) survey will approximately cover 90 square degrees at high galactic latitude, which is very useful for gravitational lensing studies as well as for the identification of various classes of interesting galactic and extragalactic objects (cf. microlensed stars, supernovae, clusters, etc.). A description of the telescope, its instrumentation and the handling of the data is also presented
Cornell Caltech Atacama Telescope (CCAT): a 25 m aperture telescope above 5000 m altitude
Full text linkCornell, California Institute of Technology (Caltech), and Jet Propulsion Lab (JPL) have joined together to study development of a 25 meter sub-millimeter telescope (CCAT) on a high peak in the Atacama region of northern Chile, where the atmosphere is so dry as to permit observation at wavelengths as short as 200 μm. The telescope is designed to deliver high efficiency images at that wavelength with a total one-half wavefront error of about 10 μm. With a 20 arc min field of view, CCAT will be able to accommodate large format bolometer arrays and will excel at carrying out surveys as well as resolving structures to the 2 arc sec resolution level. The telescope will be an ideal complement to ALMA. Initial instrumentation will include both a wide field bolometer camera and a medium resolution spectrograph. Studies of the major telescope subsystems have been performed as part of an initial Feasibility Concept Study. Novel aspects of the telescope design include kinematic mounting and active positioning of primary mirror segments, high bandwidth secondary mirror segment motion control for chopping, a Calotte style dome of 50 meter diameter, a mount capable of efficient scanning modes of operation, and some new approaches to panel manufacture. Analysis of telescope performance and of key subsystems will be presented to illustrate the technical feasibility and pragmatic cost of CCAT. Project plans include an Engineering Concept Design phase followed by detailed design and development. First Light is planned for early 2012
First results from CARMA: the combined array for research in millimeter-wave astronomy
Full text linkThe Combined Array for Research in Millimeter-wave Astronomy (CARMA) comprises the millimeter-wave antennas of the Owens Valley Radio Observatory (OVRO), the Berkeley-Illinois-Maryland Association (BIMA) Array, and the new Sunyaev-Zel'dovich Array (SZA). CARMA consists of six 10.4-m, nine 6.1-m, and eventually eight 3.5-m diameter antennas on a site at elevation 2200 m in the Inyo Mountains near Bishop, California. The array will be operated by an association that includes the California Institute of Technology and the Universities of California (Berkeley), Chicago, Illinois (Urbana-Champaign), and Maryland. Observations will be supported at wavelengths of 1 cm, 3 mm, and 1.3 mm, on baselines from 5 m to 2 km. The initial correlator will use field programmable gate array (FPGA) technology to provide all single-polarization cross-correlations on two subarrays of 8 and 15 antennas with a total bandwidth of 8 GHz on the sky. The next generation correlator will correlate the full 23-antenna array in both polarizations. CARMA will support student training, technology development, and front-line astronomical research in a wide range of fields including cosmology, galaxy formation and evolution, star and planet formation, stellar evolution, chemistry of the interstellar medium, and within the Solar System, comets, planets, and the Sun. Commissioning of CARMA began in August 2005, after relocation of the antennas to the new site. The first science observations commenced in April 2006
SPIDER: a new balloon-borne experiment to measure CMB polarization on large angular scales
Full text linkWe describe SPIDER, a novel balloon-borne experiment designed to measure the polarization of the Cosmic Microwave Background (CMB) on large angular scales. The primary goal of SPIDER is to detect the faint signature of inflationary gravitational waves in the CMB polarization. The payload consists of six telescopes, each operating in a single frequency band and cooled to 4 K by a common LN/LHe cryostat. The primary optic for each telescope is a 25 cm diameter lens cooled to 4 K. Each telescope feeds an array of antenna coupled, polarization sensitive sub-Kelvin bolometers that covers a 20 degree diameter FOV with diffraction limited resolution. The six focal planes span 70 to 300 GHz in a manner optimized to separate polarized galactic emission from CMB polarization, and together contain over 2300 detectors. Polarization modulation is achieved by rotating a cryogenic half-wave plate in front of the primary optic of each telescope. The cryogenic system is designed for 30 days of operation. Observations will be conducted during the night portions of a mid-latitude, long duration balloon flight which will circumnavigate the globe from Australia. By spinning the payload at 1 rpm with the six telescopes fixed in elevation, SPIDER will map approximately half of the sky at each frequency on each night of the flight
The Thirty Meter Telescope site testing robotic computer system
Full text linkThe Thirty Meter Telescope (TMT) project is currently testing six remote sites as candidates for the final location of the telescope. Each site has several instruments, including seeing monitors, weather stations, and turbulence profile measuring systems, each of which is computer controlled. As the sites are remote (usually hours from the nearest town), they requires a system that can control the operations of all the varied subsystems, keep the systems safe from damage and recover from errors during operation. The robotic system must also be robust enough to operate without human intervention and when internet connections are lost. It is also critical that a data archiving system diligently records all data as gathered. This paper is a discussion of the TMT site testing robotic computer system as implemented
Gattini: a multisite campaign for the measurement of sky brightness in Antarctica
Full text linkWe present the Gattini project: a multisite campaign to measure the optical sky properties above the two high altitude Antarctic astronomical sites of Dome C and Dome A. The Gattini-DomeC project, part of the IRAIT site testing campaign and ongoing since January 2006, consists of two cameras for the measurement of optical sky brightness, large area cloud cover and auroral detection above the DomeC site, home of the French-Italian Concordia station. The cameras are transit in nature and are virtually identical except for the nature of the lenses. The cameras have operated successfully throughout the past two Antarctic winter seasons and here we present the first results obtained from the returned 2006 dataset. The Gattini-DomeA project will place a similar site testing facility at the highest point on the Antarctic plateau, Dome A, with observations commencing in 2008. The project forms a small part of a much larger venture coordinated by the Polar Research Institute of China as part of the International Polar Year whereby an automated site testing facility called PLATO will be traversed into the DomeA site. The status of this exciting and ambitious project with regards to the Gattini-DomeA cameras will be presented
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