Comet C/2013 UQ4 (Catalina) first looked like an asteroid when NASA's NEOWISE team first observed it on December 31, 2013. These exposures were taken that day, when the comet was at a distance of about 2.9 AU from the sun.
NASA's Jet Propulsion Laboratory manages the NEOWISE mission for NASA's Science Mission Directorate in Washington. The Space Dynamics Laboratory in Logan, Utah, built the science instrument. Ball Aerospace & Technologies Corp. of Boulder, Colo., built the spacecraft. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.
More information on NEOWISE is online at http://neowise.ipac.caltech.edu.