Austrian astronomer who is noted for his discovery (1826) that a certain comet, now called Biela's Comet, reappeared at intervals of 6.7 years. Biela's comet underwent remarkable transformations, returning in 1845 and 1852 as a double comet and then disappearing until 1872, when its fragments returned as a meteor shower, the Andromedides, that traced the comet's orbit. Biela's discovery of the period of the comet helped astronomers confirm the suspected connection between comets and meteors. In honour of Biela's discovery, the Andromedides are called the Bielids, and a crater on the Moon was named for him.