SPACEWATCH® Observations Retire a Virtual Impactor

2018 April 25:  Minor Planet 2017 TA6, a Near-Earth Asteroid approximately 11-24 meters in diameter, was discovered by the Catalina Sky Survey on 2017 Oct 15 and listed by NASA/JPL as a potential ("Virtual") Impactor (VI).  It therefore required additional observations to refine the predictions of its trajectory with respect to Earth during its future return apparitions.  However, it had receded from Earth after discovery and had become too faint for most telescopes commonly used for astrometric measurements of asteroids.  Fortunately, however, it was targeted and recovered by SPACEWATCH® with the 4-meter Blanco telescope at the Cerro Tololo Interamerican Observatory in Chile on 2018 Apr 25 at apparent V magnitude 24.5.  It was retired from the impact risk list as a result of the astrometric measurements thus obtained.  This recovery represents SPACEWATCH®'s new emphasis on using large telescopes to observe VIs that have become too dim for most telescopes used for follow-up astrometry.