... November 17, 1996 . A Quasar in the Gamma-Ray Sky . Credit: EGRET team, Compton Observatory , NASA . Explanation : The bright object in the center of the false color image above is quasar 3C279 viewed in gamma-rays , photons with more than 40 million times the energy of visible light. ... Yet, in June of 1991 a gamma-ray telescope onboard NASA's orbiting Compton Gamma Ray Observatory unexpectedly discovered that it was one of the brightest objects in the gamma-ray sky . ... About APOD . ...