Joseph Scott Stuart (MIT Lincoln Laboratory)
Keywords: Astronomy, Astronomical Catalogs
Abstract:
In order to maximize sensitivity, optical space surveillance sensors use detectors that have good sensitivity over a wide region of the spectrum. For example, the CCD detectors for the Lincoln Near-Earth Asteroid Research (LINEAR) Project, which are nearly identical to the detectors of the Ground-based Electro-Optical Deep Space Surveillance System, have good sensitivity over the visible spectrum from 380 nanometers to beyond 1000 nanometers. However, photometric calibration of the intensities of objects (stars, satellites, asteroids, etc.) measured by these systems must be referenced to astronomical star catalogs that were measured over much narrower portions of the available spectrum. For example, the Sloan Digital Sky Survey (SDSS) Photometric Database contains photometric measurements in five bandpasses that are each about 150 nanometers wide. This paper will present a method for converting between photometric systems with different bandpasses. The method uses the measured response functions of the detectors of interest along with a model of the spectral transmissivity of the atmosphere (Stone, 1996), and a catalog of stellar spectra (Pickles, 1998) to derive polynomial functions that allow for the conversion of brightness measurements from astronomical catalogs to the bandpass of the sensor. The method has been extensively tested using data from the Lincoln Near-Earth Asteroid Research project in comparison with catalog measurements from the USNO B1.0 astrometric catalog, and the SDSS Photometric Database. Through OPAL (Optical Processing Architecture at Lincoln), this technique is being applied to ground-based and space-based sensors including the Space-Based Visible (SBV) system, the Space-Based Space Surveillance (SBSS) system, and the Space Surveillance Telescope (SST).
Date of Conference: September 12-15, 2007
Track: Astronomy and Astronomical Catalogs