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.
Comet NEOWISE was first observed by NASA's NEOWISE spacecraft on Valentine's Day, 2014. This heat-sensitive infrared image was made by combining six exposures taken by the NEOWISE mission of the newly discovered comet.
NASA's NEOWISE spacecraft opened its 'eyes' after more than two years of slumber to see the starry sky with the same clarity achieved during its prime mission. This image shows a patch of sky in the constellation Pisces.
NEOWISE, the asteroid-hunting portion of NASA's WISE mission, illustrates the differences between orbits of a typical near-Earth asteroid (blue) and a potentially hazardous asteroid, or PHA (orange). PHAs are a subset of the near-Earth asteroids (NEAs).