While optical and radio transient surveys have enjoyed a renaissance over the past decade, the dynamic infrared sky remains virtually unexplored. The infrared is a powerful tool for probing transient events in dusty regions that have high optical extinction, and for detecting the coolest of stars that are bright only at these wavelengths. The fundamental roadblocks in studying the infrared time-domain have been the overwhelmingly bright sky background (250 times brighter than optical) and the narrow field-of-view of infrared cameras (largest is 0.6 sq deg). To begin to address these challenges and open a new observational window in the infrared, we present Palomar Gattini-IR: a 25 sq degree, 300mm
aperture, infrared telescope at Palomar Observatory that surveys the entire accessible sky (20,000 sq deg) to a depth of 16.4 AB mag (J band, 1.25μm) every night. Palomar Gattini-IR is wider in area than every existing infrared camera by more than a factor of 40 and is able to survey large areas of sky multiple times. We anticipate the potential for otherwise infeasible discoveries, including, for example, the elusive electromagnetic counterparts to gravitational wave detections. With dedicated hardware in hand, and a F/1.44 telescope available commercially and cost-effectively, Palomar Gattini-IR will be on-sky in early 2017 and will survey the entire accessible sky every night for two years. We present an overview of the pathfinder Palomar Gattini-IR project, including the ambitious goal of sub-pixel imaging and ramifications of this goal on the opto-mechanical design and data reduction software.
Palomar Gattini-IR will pave the way for a dual hemisphere, infrared-optimized, ultra-wide field high cadence machine called Turbo Gattini-IR. To take advantage of the low sky background at 2.5 μm, two identical systems will be located at the polar sites of the South Pole, Antarctica and near Eureka on Ellesmere Island, Canada. Turbo Gattini-IR will survey 15,000 sq. degrees to a depth of 20AB, the same depth of the VISTA VHS survey, every 2 hours with a survey efficiency of 97%.
Detecting light reflected from exoplanets by direct imaging is the next major milestone in the search for, and characterization of, an Earth twin. Due to the high-risk and cost associated with satellites and limitations imposed by the atmosphere for ground-based instruments, we propose a bottom-up approach to reach that ultimate goal with an endeavor named MAPLE. MAPLE first project is a stratospheric balloon experiment called MAPLE-50. MAPLE-50 consists of a 50 cm diameter off-axis telescope working in the near-UV. The advantages of the near-UV are a small inner working angle and an improved contrast for blue planets. Along with the sophisticated tracking system to mitigate balloon pointing errors, MAPLE-50 will have a deformable mirror, a vortex coronograph, and a self-coherent camera as a focal plane wavefront-sensor which employs an Electron Multiplying CCD (EMCCD) as the science detector. The EMCCD will allow photon counting at kHz rates, thereby closely tracking telescope and instrument-bench-induced aberrations as they evolve with time. In addition, the EMCCD will acquire the science data with almost no read noise penalty. To mitigate risk and lower costs, MAPLE-50 will at first have a single optical channel with a minimum of moving parts. The goal is to reach a few times 109 contrast in 25 h worth of flying time, allowing direct detection of Jovians around the nearest stars. Once the 50 cm infrastructure has been validated, the telescope diameter will then be increased to a 1.5 m diameter (MAPLE-150) to reach 1010 contrast and have the capability to image another Earth.
We present new results from the first search for transiting exoplanets undertaken from the High Arctic: the AWCam (Arctic Wide-field Cameras) survey. The survey, which has been operating for 2.5 years, is based at 80 degrees North on Ellesmere Island in the Canadian High Arctic. The small telescopes monitor 70,000 bright stars in a several-hundred square-degree region around Polaris, with milli-magnitude photometric precision, and are capable of discovering giant planets around 10,000 bright, nearby solar-type stars. We present the first longterm monitoring results from the AWCams, including an assessment of the site characteristics and the systems' long-term performance. The High-Arctic site provided excellent survey efficiency, without diurnal windowing and largely uninterrupted by clouds. Useful data was obtained over the entire survey field 71% of the time; the sky was clear 62% of the time. One pristine clear, dark period in winter 2012/13 persisted for 480 hours. In 2012/13 we recorded a period of 480 hours of continuous photometric conditions, attaining 3-4 millimag photometric stability over the entire period. We report the long-term photometric performance of the AWCam systems and detail the discovery of a bright (V=8) low-amplitude eclipsing binary. Finally, we present a concept for an extremely-wide-field arctic survey based on the Evryscope telescope-array design.
The Earth's polar regions offer unique advantages for ground-based astronomical observations with its cold and dry climate, long periods of darkness, and the potential for exquisite image quality. We present preliminary results from a site-testing campaign during nighttime from October to November 2012 at the Polar Environment Atmospheric Research Laboratory (PEARL), on a 610-m high ridge near the Eureka weatherstation on Ellesmere Island, Canada. A Shack-Hartmann wavefront sensor was employed, using the Slope Detection and Ranging (SloDAR) method. This instrument (Mieda et al, this conference) was designed to measure the altitude, strength and variability of atmospheric turbulence, in particular for operation under Arctic conditions. First SloDAR optical turbulence profiles above PEARL show roughly half of the optical turbulence confined to the boundary layer, below about 1 km, with the majority of the remainder in one or two thin layers between 2 km and 5 km, or above. The median seeing during this campaign was measured to be 0.65 arcsec.
Observations from near the Eureka station on Ellesmere Island, in the Canadian High Arctic at 80° North, benefit from 24-hour darkness combined with dark skies and long cloud-free periods during the winter. Our first astronomical surveys conducted at the site are aimed at transiting exoplanets; compared to mid-latitude sites, the continuous darkness during the Arctic winter greatly improves the survey’s detection effciency for longer-period transiting planets. We detail the design, construction, and testing of the first two instruments: a robotic telescope, and a set of very wide-field imaging cameras. The 0.5m Dunlap Institute Arctic Telescope has a 0.8-square-degree field of view and is designed to search for potentially habitable exoplanets around low-mass stars. The very wide field cameras have several-hundred-square-degree fields of view pointed at Polaris, are designed to search for transiting planets around bright stars, and were tested at the site in February 2012. Finally, we present a conceptual design for the Compound Arctic Telescope Survey (CATS), a multiplexed transient and transit search system which can produce a 10,000-square-degree snapshot image every few minutes throughout the Arctic winter.
We present the first measurements of the near-infrared (NIR), specifically the J-band, sky background in the Canadian High Arctic. There has been considerable recent interest in the development of an astronomical observatory in Ellesmere Island; initial site testing has shown promise for a world-class site. Encouragement for our study came from sky background measurements on the high Antarctic glacial plateau in winter that showed markedly lower NIR emission when compared to good mid-latitude astronomical sites due to reduced emission from the Meinel bands, i.e. hydroxyl radical (OH) airglow lines. This is possibly a Polar effect and may also be present in the High Arctic. To test this hypothesis, we carried out an experiment which measured the the J-band sky brightness in the High Arctic during winter. We constructed a zenith-pointing, J-band photometer, and installed it at the Polar Environment Atmospheric Research Laboratory (PEARL) near Eureka, Nunavut (latitude: 80° N). We present the design of our ruggedized photometer and our results from our short PEARL observing campaign in February 2012. Taken over a period of four days, our measurements indicate that the
J-band sky brightness varies between 15.5-15.9 mag arcsec2; with a measurement uncertainty of 0.15 mag. The
uncertainty is entirely dominated by systematic errors present in our radiometric calibration. On our best night, we measured a fairly consistent sky brightness of 15.8 ± 0.15 mag arcsec2. This is not corrected for atmospheric extinction, which is typically < 0.1 mag in the J-band on a good night. The measured sky brightness is
comparable to an excellent mid-latitude site, but is not as dark as claimed by the Antarctic measurements. We
discuss possible explanations of why we do not see as dark skies as in the Antarctic. Future winter-long sky
brightness measurements are anticipated to obtain the necessary statistics to make a proper comparison with
the Antarctic measurements.
Mountains along the northwestern coast of Ellesmere Island, Canada, possess the highest peaks nearest the Pole. This
geography, combined with an atmospheric thermal inversion restricted to below ~1000 m during much of the long arctic
night, provides excellent opportunities for uninterrupted cloud-free astronomy - provided the challenges of these
incredibly remote locations can be overcome. We present a miniaturized robotic observatory for deployment on a High
Arctic mountaintop. This system tested the operability of precise optical instruments during winter, and the logistics of
installation and maintenance during summer. It is called Ukpik after the Inuktitut name for the snowy owl, and was
deployed at two sites accessible only by helicopter, each north of 82 degrees latitude; one on rock at 1100 m elevation
and another on a glacier at 1600 m. The instrument suite included at first an all-sky-viewing camera, with the later
addition of a small telescope to monitor Polaris, both protected by a retractable weather-proof enclosure. Expanding this
to include a narrow-field drift-scanning camera for studying extra-solar planet transits was also investigated, but not
implemented. An unique restriction was that all had to be run on batteries recharged primarily by a wind turbine.
Supplementary power came from a methanol fuel-cell electrical generator. Communications were via the Iridium
satellite network. The system design, and lessons learned from three years of operation are discussed, along with
prospects for time-domain astronomy from isolated, high-elevation polar mountaintops.
We report the first measurements of 225 GHz atmospheric opacity at Summit Camp (Latitude 72°.57 N; Longitude
38°.46 W; Altitude 3250 m) in Greenland and the Polar Environment Atmospheric Research Laboratory
(PEARL: Latitude 80°.05 N; Longitude 86°.42 W; Altitude 600 m) in Northern Canada with a tipping radiometer.
Summit Camp and PEARL are research stations mostly interested in meteorology and geophysics, and
they are potentially excellent sites for astronomical observations at sub-millimeter wavelength. We purchased
a tipping radiometer from Radiometer Physics GmbH. After a test run at the summit of Mauna Kea, Hawaii,
the radiometer was deployed to PEARL in February 2011, and relocated to Summit Camp in August 2011. The
atmospheric opacity has been monitored from February 14th to May 10th, 2011 at PEARL and since August
2011 at Summit Camp. The median values of the measured opacity at PEARL ranged from 0.11 in February to 0.19 in May; Summit Camp varied in the range from 0.04 to 0.18 between August 2011 and May 2012. Summit
Camp in Greenland is expected to be an excellent site for sub-millimeter and Terahertz astronomy, and we plan
to set up there a 12-m telescope for VLBI and single-dish observations.
As part of a program to measure and evaluate atmospheric turbulence on mountains at the most northerly tip of North
America, we have deployed two SODARs and a lunar scintillometer at the Polar Environment Atmospheric Research
Lab (PEARL) located on a 600m-high ridge near Eureka on Ellesmere Island, at 80° latitude. This paper discusses the
program and presents a summary of ground-layer turbulence and seeing measurements from the 2009-10 observing
Coastal mountains at Canada's northern tip possess many of the desirable properties that make the Antarctic glacial
plateau attractive for astronomy: they are cold, high, dry, and in continuous darkness for several months in winter.
Satellite images suggest that they should also benefit from clear skies for a fraction of time comparable to the best mid-latitude
sites, and conventional site-selection criteria point to good seeing. In order to confirm these conditions, we are
testing three mountain sites on northwestern Ellesmere Island, in Nunavut. On each we have installed a compact,
autonomous site-testing station consisting of a meteorological station, a simple optical/near-infrared camera for sensing
cloud cover, and - at one site - a more advanced all-sky viewing camera. The systems were deployed by helicopter and
run on batteries recharged by wind (a compact methanol fuel cell is under study as a supplementary power source).
Effective two-way communications via the Iridium satellite network allows a limited number of highly compressed
images to be transferred. The full-winter dataset is stored at the site on flash-drives, thus requiring a return visit to
retrieve, but day-to-day station performance can be assessed using telemetry and a computer model. Based on site-testing
results, the plan is to select one site for the addition of a seeing monitor and a small but scientifically productive
The next generation of ground-based telescopes will have apertures of 20 meters or more and will be increasingly dependent on active and adaptive optics (AO) to deliver good image quality. A numerical model of the complete telescope system, including optical, mechanical, and atmospheric seeing effects, will be a vital tool during the design process. The Thirty Meter Telescope (TMT) / Very Large Optical Telescope (VLOT) Integrated Model (IM) is written in MATLAB and runs on a Windows PC. One goal of the IM is to study the interaction of various AO designs with several telescope configurations. This requires the inclusion of an AO simulation engine; the IDL-based CAOS code was chosen as a starting point. Socket based software was developed to allow MATLAB MEX functions called from the IM to control the CAOS code running on a Linux PC. Software was also developed to allow MATLAB MEX functions to interact with IDL on the same Windows computer using callable IDL.