Speaker
Description
In this study, we propose the method of frame stacking which is implemented in celestial (equatorial) coordinate system. This method allows to prolong the “effective exposure time” of near-Earth objects (NEOs) increasing the efficiency of capturing faint objects. Additionally, it can be realized using CCD frames obtained by several optical systems simultaneously or at different epochs.
Stacking of CCD frames is quite common practice in astronomical imaging. It is usually done by comparing patterns or directly overlying images and requires all frames to be obtained by the same telescopes and in similar circumstances. The proposed use of equatorial coordinates allows to stack frames, which have different scales, distortions, framing, and epochs. This approach requires an astrometric solution for all involved frames, i.e., transformation from pixel coordinates to equatorial coordinate system. Stacked frame is generated in a rectangular coordinate system, having as coordinates right ascension and declination. Thus, implementation of this approach ensures the possibility to combine frames obtained by different optical systems at different locations, as well as to increase the brightness of NEOs also in situations where a number of circumstances, such as weather, astroclimate, hardware capabilities, specific locations, are forcing to put up with short exposures, small sensors and bright sky background.
In this work the methodology of astrometric processing is presented. We provide observation cases highlighting advantages of the method of frame stacking for NEO detection and tracking. The software package used in this study was developed at the Institute of Geodesy and Geoinformatics (GGI). Observation results were obtained by twin 41-cm telescope system of the University of Latvia.
Acknowledgement: The research is financed by the Recovery and Resilience Facility project "Internal and External Consolidation of the University of Latvia", No. 5.2.1.1.i.0/2/24/I/CFLA/007.