Every clear night there is a patrol of the night skies for hazardous asteroids conducted by telescopes. The Catalina Sky Survey (CSS) is operated by the University of Arizona and the California Institute of Technology.
Patrolling the skies by taking hundreds of wide field photographs each night allows the astronomers to scan these photos for moving asteroids. Thousands of asteroids have been found but so have other sky events such as supernovas, variable stars and other brightening-dimming events.
As reported by a University of Arizona press release: "Using images obtained by the UA's asteroid-hunting Catalina Sky Survey, the Catalina Real-Time Transient Survey, or CRTS, lets CalTech astronomers systematically scan the heavens for these dynamic objects, resulting in an unprecedented data set that will allow scientists worldwide to pursue new research. The new data set is based on observations taken with the 0.7-meter telescope on Mt. Bigelow in Arizona. The observations were part of the Catalina Sky Survey, a search for Near-Earth Objects, or NEOs – asteroids that may pose a threat to Earth –conducted by astronomers at the UA. By repeatedly taking pictures of large swaths of the sky and comparing these images to previous ones, the CRTS is able to monitor the brightness of about half-billion objects, allowing it to search for those that dramatically brighten or dim. In this way, the CRTS team identified tens of thousands of variables, maximizing the science that can be gleaned from the original data.The new data set contains the so-called brightness histories of a total of 200 million stars and other objects, incorporating more than 20 billion independent measurements."
In essence these photos allow astronomers to mine the sky images for transient events and provide an invaluable snapshot of a particular region of the sky on a specific date and time. This comes in very handy if some new astronomical event occurs in the future and we want to know what the sky looked like before in that same spot.
Every clear night will only add to this treasure trove of data. Read More About It: http://uanews.org/node/43845.
Sky Guy in VA