In Computer Vision, the sky color is used for lighting correction, image color enhancement, horizon alignment, image indexing, and outdoor image classification and in many other applications. In this article, for robust color based sky segmentation and detection, usage of lighting correction for sky color detection is investigated. As such, the impact of color constancy on sky color detection a...

We present observations of a new double-image gravitational lens system, ULAS J082016.1+081216, of image separation 2. 3 and high (∼6) flux ratio. The system is selected from the Sloan Digital Sky Survey spectroscopic quasar list using new high-quality images from the UKIRT Deep Sky Survey (UKIDSS). The lensed quasar has a source redshift of 2.024, and we identify the lens galaxy as a faint red...

The Antarctic Plateau provides the best terrestrial sites for infrared (IR) and submillimetre (sub-mm) astronomy. In this paper we examine the relative importance of temperature, aerosol content and precipitable water vapour to determine which parameters have the greatest influence on atmospheric transmission and sky brightness. We use the atmospheric modelling program MODTRAN to model the obse...

We present and describe a catalog of galaxy photometric redshifts (photo-z’s) for the Sloan Digital Sky Survey (SDSS) Data Release 6 (DR6). We use the Artificial Neural Network (ANN) technique to calculate photo-z’s and the Nearest Neighbor Error (NNE) method to estimate photo-z errors for ∼ 77 million objects classified as galaxies in DR6 with r < 22. The photo-z and photo-z error estimators a...

The pattern-matching algorithms originally developed for Multi-angle Imaging SpectroRadiometer (MISR) (flying on the Earth Observing System (EOS) Terra platform) cloud retrieval have also proven useful in independently providing quality assurance of the coregistration of multiangle measurements with the nadir view. Two new techniques developed to test the coregistration are described in this pa...

The all-sky monitor on the Rossi X-Ray Timing Explorer has been monitoring the sky in the 1.5–12 keV band since late February. The instrument consists of three coded-aperture cameras that can be rotated to view different regions by a motorized drive assembly. Intensities of 1100 known sources are obtained via least-squares fits of shadow patterns to the data and compiled to form X-ray light cur...

This paper presents a practical method for the development of spectral reflectance libraries under sub-optimal sky conditions. Although there are commercially available spectrometers which simultaneously measure both downwelling and upwelling radiance to mitigate the impact of sub-optimal sky conditions, these spectrometers only record in the visible and near infra-red. There are presently no c...

Knowing in advance the visibility of a given object is important when planning an observation. New amateurs usually search only bright objects since they present smaller difficulties for finding and observing them, except perhaps under severe conditions (e.g., city, full moon). Nevertheless, amateurs gradually extend their observations to more challenging targets, fainter and more elusive. Thes...

We present and describe a catalog of galaxy photometric redshifts (photo-z’s) for the Sloan Digital Sky Survey (SDSS) Data Release 6 (DR6). We use the Artificial Neural Network (ANN) technique to calculate photo-z’s and the Nearest Neighbor Error (NNE) method to estimate photo-z errors for ∼ 77 million objects classified as galaxies in DR6 with r < 22. The photo-z and photo-z error estimators a...

In radio telescope arrays, the complex receiver gains and sensor noise powers are initially unknown and have to be calibrated. Gain calibration can enhance the quality of astronomical sky images and, moreover, improve the effectiveness of array signal processing techniques for interference mitigation and spatial filtering. A challenging aspect is that the signal-to-noise ratio (SNR) is usually ...