Career
He is a Fellow and former President of the International Association of Astronomical Artists. PH1, the first planet discovered in a quadruple star system. He showed that suspected transits in the Kepler Space Telescope data of the system were indeed due to a planet transiting the eclipsing binary in the system.
In 2014, he helped discover and characterize planets in three additional stellar systems, including Kepler-88 and Kepler-247.
Asteroid (79912) Terrell is named in his honor.