Astronomers using NERSC's Real-Time Detection pipeline uncovered supernova SN2009av-1a in the act of exploding. At left, the image of a galaxy 800 million light-years away was created by layering observations taken by the Palomar Transient Factory camera from February 23-27. Second from left is the image captured by the PTF camera on February 28. Next, using the NERSC pipeline to digitally subtract the earlier image from the new one, scientists exposed this cosmic transient, a supernova. At right, subtracting the previous images from one taken March 2 showed the source getting brighter. Follow-up observations caught the Type Ia supernova, now called SN2009av, at peak brightness.