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Author Aubé, M.; Fortin, N.; Turcotte, S.; García, B.; Mancilla, A.; Maya, J.
Title Evaluation of the Sky Brightness at Two Argentinian Astronomical Sites Type Journal Article
Year 2014 Publication Publications of the Astronomical Society of the Pacific Abbreviated Journal Publications of the Astronomical Society of the Pacific
Volume Issue Pages 000-000
Keywords Skyglow; light pollution; astronomical observatories; sky brightness; site selection; LEO ++; El Leoncito; Kitt Peak; Mont-Mégantic; Argentina
Abstract Light pollution is a growing concern at many levels, especially for the astronomical community. Indeed, not only does artificial lighting veil celestial objects, it disturbs the measurement of many atmospheric phenomena. The sky brightness is one of the most relevant parameters for astronomical site selection. Our goal is to evaluate the sky brightness of two Argentinian observation sites: LEO ++ and El Leoncito. Both sites were preselected to host the Cherenkov Telescope Array. This project consists of an arrangement of many telescopes that can measure high-energy gamma ray emissions via their Cherenkov radiation produced when entering the earth’s atmosphere. In this paper, we describe the measurement methods used to determine whether those sites are valuable or not. We compared our results with the sky radiance of different renowned astronomical sites (Kitt Peak, Arizona, and Mont-Mégantic, Québec, Canada). Among our results, we found that LEO ++ is a good site, however the presence of a low layer of local aerosol can introduce uncertainties in the measurements. Consequently, El Leoncito would be a better option for such an installation. This latter site shows very low sky brightness levels, which are optimal for low light detection.
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ISSN 0004-6280 ISBN Medium
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Notes Approved no
Call Number IDA @ john @ Serial 1071
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Author Benn, C.R.; Ellison, S.L.
Title La Palma night-sky brightness Type Report
Year 1998 Publication La Palma Technical Reports Abbreviated Journal
Volume Issue 115 Pages
Keywords Skyglow; solar cycle; airglow; zodiacal light; light pollution; observatories; *Light
Abstract The brightness of the moonless night sky above La Palma was measured on 427 CCD images taken with the Isaac Newton and Jacobus Kapteyn Telescopes on 63 nights during 1987 – 1996. The median sky brightness at high elevation, high galactic latitude and high ecliptic latitude, at sunspot minimum, is B = 22.7, V = 21.9, R = 21.0, similar to that at other dark sites. The main contributions to sky brightness are airglow and zodiacal light. The sky is brighter at low ecliptic latitude (by 0.4 mag); at solar maximum (by 0.4 mag); and at high airmass (0.25 mag brighter at airmass 1.5). Light pollution (line + continuum) contributes < 0.03 mag in U, approximately 0.02 mag in B, approximately 0.10 mag in V, approximately and 0.10 mag in R at the zenith.
Address Isaac Newton Group, Apartado 321, 38780 Santa Cruz de La Palma, Spain
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Notes Lots of useful theory on the various contributions to natural sky background level and expected surface brightnesses Approved no
Call Number IDA @ john @ Serial 1101
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Author Hampf, D.; Rowell, G.; Wild, N.; Sudholz, T.; Horns, D.; Tluczykont, M.
Title Measurement of night sky brightness in southern Australia Type Journal Article
Year 2011 Publication Advances in Space Research Abbreviated Journal Advances in Space Research
Volume 48 Issue 6 Pages 1017-1025
Keywords Observatories and site testing; Airglow and aurorae; Photometric, polarimetric, and spectroscopic instrumentation
Abstract Night sky brightness is a major source of noise both for Cherenkov telescopes as well as for wide-angle Cherenkov detectors. Therefore, it is important to know the level of night sky brightness at potential sites for future experiments.

The measurements of night sky brightness presented here were carried out at Fowler’s Gap, a research station in New South Wales, Australia, which is a potential site for the proposed TenTen Cherenkov telescope system and the planned wide-angle Cherenkov detector system HiSCORE.

A portable instrument was developed and measurements of the night sky brightness were taken in February and August 2010. Brightness levels were measured for a range of different sky regions and in various spectral bands.

The night sky brightness in the relevant wavelength regime for photomultipliers was found to be at the same level as measured in similar campaigns at the established Cherenkov telescope sites of Khomas, Namibia, and at La Palma. The brightness of dark regions in the sky is about 2 × 1012 photons/(s sr m2) between 300 nm and 650 nm, and up to four times brighter in bright regions of the sky towards the galactic plane. The brightness in V band is 21.6 magnitudes per arcsec2 in the dark regions. All brightness levels are averaged over the field of view of the instrument of about 1.3 × 10&#8722;3 sr.

The spectrum of the night sky brightness was found to be dominated by longer wavelengths, which allows to apply filters to separate the night sky brightness from the blue Cherenkov light. The possible gain in the signal to noise ratio was found to be up to 1.2, assuming an ideal low-pass filter.
Address Department of Physics, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
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ISSN 0273-1177 ISBN Medium
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Notes Approved no
Call Number IDA @ john @ Serial 189
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Author Massey, P.; Foltz, C. B.
Title The Spectrum of the Night Sky over Mount Hopkins and Kitt Peak: Changes after a Decade1 Type Journal Article
Year 2000 Publication Publications of the Astronomical Society of the Pacific Abbreviated Journal Publ Astron Soc Pac
Volume 112 Issue 770 Pages 566-573
Keywords Kitt Peak; observatories; Arizona; skyglow; light pollution; measurements
Abstract Recent (1998–1999) absolute spectrophotometry of the night sky over two southern Arizona astronomical sites, Kitt Peak and Mount Hopkins, is compared to similar data obtained in 1988 at each site. The current zenith sky brightness in the range &#8764;3700–6700 Å is essentially identical at the two sites and is as dark now as Palomar Observatory was in the early 1970s, when it was generally considered a premier dark observing site. Converted to broadband measurements, our spectrophotometry is equivalent to , mag arcsec&#8722;2, for the zenith night sky. The contribution of high&#8208;pressure sodium street lights to broadband V is about 0.2 mag arcsec&#8722;2, comparable to the strong airglow O i &#955;5577 line. During the period from 1988 to 1998–1999, the zenith sky brightness increased only modestly, with the largest changes being seen for Kitt Peak, where the zenith sky has brightened by &#8776;0.1–0.2 mag arcsec&#8722;2 in the blue&#8208;optical region. For Kitt Peak we also have both 1988 and 1999 observations at modestly large zenith distances ( ). In the directions away from Tucson, the sky has brightened by &#8776;0.35 mag arcsec&#8722;2 over the intervening decade. Toward Tucson the change has been larger, approximately 0.5 mag arcsec&#8722;2. In most directions the increase in the sky brightness has lagged behind the fractional increase in population growth, which we attribute to good outdoor lighting ordinances, a fact which is further reflected in the decrease in Hg emission. However, our results emphasize the need for diligent attention as developments creep closer to our observing sites.
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Series Editor Series Title Abbreviated Series Title
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ISSN 0004-6280 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 264
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Author Noll, S.; Kausch, W.; Barden, M.; Jones, A.M.; Szyszka, C.; Kimeswenger, S.; Vinther, J.
Title An atmospheric radiation model for Cerro Paranal: I. The optical spectral range* Type Journal Article
Year 2012 Publication Astronomy & Astrophysics Abbreviated Journal A&A
Volume 543 Issue Pages A92
Keywords atmospheric effects; site testing; radiative transfer; radiation mechanisms: general; scattering; techniques; spectroscopic; modeling; observatories; Cerro Paranal
Abstract Aims. The Earth’s atmosphere affects ground-based astronomical observations. Scattering, absorption, and radiation processes deteriorate the signal-to-noise ratio of the data received. For scheduling astronomical observations it is, therefore, important to accurately estimate the wavelength-dependent effect of the Earth’s atmosphere on the observed flux.

Methods. In order to increase the accuracy of the exposure time calculator of the European Southern Observatory’s (ESO) Very Large Telescope (VLT) at Cerro Paranal, an atmospheric model was developed as part of the Austrian ESO In-Kind contribution. It includes all relevant components, such as scattered moonlight, scattered starlight, zodiacal light, atmospheric thermal radiation and absorption, and non-thermal airglow emission. This paper focuses on atmospheric scattering processes that mostly affect the blue (<0.55&#8201;&#956;m) wavelength regime, and airglow emission lines and continuum that dominate the red (>0.55&#8201;&#956;m) wavelength regime. While the former is mainly investigated by means of radiative transfer models, the intensity and variability of the latter is studied with a sample of 1186 VLT FORS&#8201;1 spectra.

Results. For a set of parameters such as the object altitude angle, Moon-object angular distance, ecliptic latitude, bimonthly period, and solar radio flux, our model predicts atmospheric radiation and transmission at a requested resolution. A comparison of our model with the FORS&#8201;1 spectra and photometric data for the night-sky brightness from the literature, suggest a model accuracy of about 20%. This is a significant improvement with respect to existing predictive atmospheric models for astronomical exposure time calculators.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0004-6361 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 274
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