Comet PANSTARRS (C/2011 L4) over the VLA radio telescope array in New Mexico, March 17, 2013. The landscape is lit by the nearly quarter Moon high in the sky out of frame. This is a composite of two images taken moments apart: a 50-second untracked exposure for the ground and a 25-second tracked exposure for the sky, so both sky and ground are sharp. All at f/2.8 with the 50mm Sigma lens on the Canon 60Da at ISO 400. Position worked out with Photographers Ephemeris.
The Amazing Sky 