Astrometry and Time-Resolved Photometry from Streaks Using Calibrated Ultra-Wide Field of View Cameras

摘要

Extracting the astrometry and photometry of an observed object in an optical image can be complicated by a number of factors. Wide-angle lenses can introduce significant distortion into images. Popular methods for correcting for distortion assume basic symmetries in optical systems that may not be reflected in reality. Additionally, the photometric intensity and corresponding uncertainty of a streaking object should be extracted in an information optimal manor. This paper approaches both of these problems separately. First, an empirical method for image calibration based on a Delaunay triangulation with vertices defined by observed and catalog star locations is outlined. This method is theoretically capable of less than 0.8 pixel residual error across the image assuming correct association between the observed stars and catalog. Next a method is discussed for information optimal streak extraction based on breaking an observed streak into constant intensity streak segments. Both an analytical and computational method for determining the appropriate number of segments are discussed. The method for extracting the streak is then demonstrated against a sub-optimal method to show that the method extracts all observable information in the streak. These algorithms improve over existing methods for extracting streaking space object information from wide-angle images.