Deep co-added sky from catalina sky survey images

ABSTRACT A number of synoptic sky surveys are underway or being planned. Typically, they done with small telescopes and relatively short exposure times. search for transient variable sources involves comparison deeper baseline images, ideally obtained through the same telescope camera. With that in mind, we have stacked images from 0.68 m Schmidt on Mt. Bigelow taken over 10 yr as part Catalina Sky Survey. In order to generate deep reference Real-time Transient Survey (CRTS), close 0.8 million 8000 fields covering 27 000 sq. deg gone into stack goes up 3 mag than individual images. CRTS system does not use a filter imaging; hence, there is no standard passband which optical magnitude measured. We estimate depth by comparing these wide-band unfiltered co-added g band find image ranges 22.0 24.2 across sky, 200-image attaining an equivalent AB sensitivity 22.8. compared various state-of-the-art software packages co-adding astronomical used swarp stacking. describe here details process adopted. This methodology may be useful other panoramic imaging applications, well. The available server at Inter-University Centre Astronomy Astrophysics.