Three-element radiointerferometer with very long baselines

The technical features and operation are described for a very long baseline three element radiointerferometer based on the existing Simeiz-Pushchino radiointerferometer with the addition of a third Earth station located near Yevpatoriya. All antennas at the ground station complexes employ identical sets of equipment operating at a wavelength of 1.35 cm. At Simeiz and Pushchino, 22 meter antennas are used, while the one at Yevpatoriya has a diameter of 70 meters. Antenna characteristics and operation are discussed. The length of baselines is as follows: Yevpatoriya-Simeiz 108 km, Simeiz-Pushchino 1,150 km, Pushchino-Yevpatoroya 1,116 km. First observations with the radiointerferometer were conducted using H2O lines from Orion-K1, W51M, W49N and W30H to check out the system and calibrate amplitude and phase. The system makes possible studies of objects measuring 83 to 2.3 milliseconds of arc. Maximum sensitivity on the short leg (Yevpatoriya-Simeiz) is 20 mJy at 250 kHz and integration time of 100 secs.