Hat Creek Observatory A radio astronomy observatory in California operated by the University of California, Berkeley at an altitude of 1024 meters. The 26-meter dish, once used for millimeter-wave astronomy, blew down in Jan. 1993. The remaining major instrument at the site is the Berkeley-Illinois-Maryland Association array (BIMA array) – a millimeter-wave interferometer. The array consists of ten dishes, each of 6-meter diameter, on tracks that stretch 300 m E–W and 200 m N–S. It can observe at wavelengths between 1.3 and 2.6 mm.