تقرير
Sky Variability in the y Band at the LSST Site
| العنوان: | Sky Variability in the y Band at the LSST Site |
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| المؤلفون: | High, F. William, Stubbs, Christopher W., Stalder, Brian, Gilmore, David Kirk, Tonry, John L. |
| سنة النشر: | 2010 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Instrumentation and Methods for Astrophysics |
| الوصف: | We have measured spatial and temporal variability in the y band sky brightness over the course of four nights above Cerro Tololo near Cerro Pachon, Chile, the planned site for the Large Synoptic Survey Telescope (LSST). Our wide-angle camera lens provided a 41 deg field of view and a 145 arcsec pixel scale. We minimized potential system throughput differences by deploying a deep depletion CCD and a filter that matches the proposed LSST y_3 band (970 nm-1030 nm). Images of the sky exhibited coherent wave structure, attributable to atmospheric gravity waves at 90 km altitude, creating 3%-4% rms spatial sky flux variability on scales of about 2 degrees and larger. Over the course of a full night the y_3 band additionally showed highly coherent temporal variability of up to a factor of 2 in flux. We estimate the mean absolute sky level to be approximately y_3 = 17.8 mag (Vega), or y_3 = 18.3 mag (AB). While our observations were made through a y_3 filter, the relative sky brightness variability should hold for all proposed y bands, whereas the absolute levels should more strongly depend on spectral response. The spatial variability presents a challenge to wide-field cameras that require illumination correction strategies that make use of stacked sky flats. The temporal variability may warrant an adaptive y band imaging strategy for LSST, to take advantage of times when the sky is darkest. Comment: 8 pages, 5 figures, accepted to PASP. Minor changes from referee report and editor's revisions. |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1086/653715 |
| الوصول الحر: | http://arxiv.org/abs/1002.3637Test |
| رقم الانضمام: | edsarx.1002.3637 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1086/653715 |
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