English: Asteroid 1994 CJ1 is only the second equal-mass binary system found in the near-Earth region. The first such system known, (69230) Hermes, was also discovered by Arecibo back in 2003. This is a radar image of the 1994 CJ1 binary system with resolution of 75 meters per pixel. Rather than having one large and one small component, the 1994 CJ1 system is made up of two very similar-size objects, each less than 150 m in diameter (500 feet or half the size of the Arecibo telescope). In addition to being a rare equal-mass binary, 1994 CJ1 may also be the smallest known binary asteroid. Often the components in a binary asteroid system are at least a few hundred meters in diameter.