Clear sky fraction above Indonesia: an analysis for astronomical site selection

We report a study of cloud cover over Indonesia based on meteorological satellite data, spanning over the past 15 years (from 1996 to 2010) in order to be able to select a new astronomical site capable to host a multi-wavelength astronomical observatory. High spatial resolution of meteorological satellite data acquired from {\it Geostationary Meteorological Satellite 5} ({\it GMS 5}), {\it Geostationary Operational Environmental Satellite 9} ({\it GOES 9}), and {\it Multi-functional Transport Satellite-1R} ({\it MTSAT-1R}) are used to derive yearly average clear fractions over the regions of Indonesia. This parameter is determined from temperature measurement of the IR3 channel (water vapor, 6.7 $\mu$m) for high altitude clouds (cirrus) and from the IR1 channel (10.7 $\mu$m) for lower altitude clouds. Accordingly, an algorithm is developed to detect the corresponding clouds. The results of this study are then adopted to select the best possible sites in Indonesia to be analysed further by performing in situ measurements planned for the coming years. The results suggest that regions of East Nusa Tenggara, located in south-eastern part of Indonesia, are the most promising candidates for such an astronomical site. Yearly clear sky fraction of this regions may reach better than 70 per cent with an uncertainty of 10 per cent.Comment: 15 pages, 13 figures, and 4 table

THE ROTATION VIBRATION ANALYSIS OF THE ν1\nu_{1} AND ν3\nu_{3} BANDS OF OZONE IN THE 9-MICRON REGION

$^{1}$S.A. Clough, Symposium on Molecular Structure and Spectroscopy, The Ohio State University, Columbus, Ohio, June 11-15-1962, Paper K4.Author Institution: Block Associates; AFCRALA computational procedure previously $described^{1}$ has been utilized in the determination of constants for the $\nu_{1}$ and $\nu_{3}$ bands of ozone. Four hundred lines have been fitted by the method of least squares to each band and an absorption contour has been calculated which is in excellent agreement with the observed spectrum in this region between 8.7 and 10.0 microns. The transition frequencies and intensities up to J=50 have been calculated by diagonalizing the asymmetric rotor Hamiltonian with distortion included. Final constants for both bands will be presented

THE REFRACTIVE INDEX OF OZONE IN THE VISIBLE AND NEAR INFRARED SPECTRAL REGIONS

$^{1}$P. W. Langhoff and M. Karplus, J. Opt. Soc. Am. 59, 863 (1969).""Author Institution: Air Force Cambridge Research LaboratoriesAn asymmetric Michelson interferometer has been constructed in order to measure the refractive index of ozone. Optical dispersion measurements have been carried out between 3800 {\AA} and 2.5 microns with an absolute accuracy of one part in $10^{6}$. The results have been interpreted with a two term Sellmeier equation as well as the more recent procedure proposed by Langhoff and $Karplus.^{1}$ The extrapolation of the data to long wavelengths has been used to examine dielectric constant values reported in the literature