Cosmic microwave telescope. Daytime view of the dish antenna of a radio telescope at Owens Valley in California, USA. This cosmic microwave telescope has a dish with a diameter of 40 metres (130 feet). Microwaves are radio waves with wavelengths between about 1 millimetre and 1 metre. The cosmic microwave telescope is one of a number of types of radio telescope at Owens Valley station. In the background can be seen the Caltech millimetre array. Owens Valley also has a 25 metre diameter radio telescope which forms part of the Very Long Baseline Array (VLBA) network. This network consists of ten VLBA stations which together act like a giant telescope.