Space-VLBI observations of OH maser OH34.26+0.15: low interstellar scattering

We report on the first space-VLBI observations of the OH34.26+0.15 maser in two main line OH transitions at 1665 and 1667 MHz. The observations involved the space radiotelescope on board the Japanese satellite HALCA and an array of ground radio telescopes. The map of the maser region and images of individual maser spots were produced with an angular resolution of 1 milliarcsec which is several times higher than the angular resolution available on the ground. The maser spots were only partly resolved and a lower limit to the brightness temperature 6x10^{12} K was obtained. The maser seems to be located in the direction of low interstellar scattering, an order of magnitude lower than the scattering of a nearby extragalactic source and pulsar.Comment: 8 pages, 2 tables, 9 figures, accepted for publication in MNRA

Radioholographic adjustment of the reflector antenna TNA-1500 in Medvezhy Ozera

The report presents results of mirror surface adjustment on one of largest Russian fully steerable radiotelescopes — 64-meter antenna in space communication center Medvezhy Ozera near Moscow. Radioholographic measurements with 4 GHz satellites signals were fulfilled on this antenna in 1995-96. Restored map of main mirror shows surface deviations near of 2 mm rms. Rms difference of the maps measured under identical external conditions was 0.1 mm. After partial adjustment of mirror surface an antenna efficiency was increased from 0.51 to 0.65 at 5-cm band

International low-frequency very-long-baseline interferometry network project milestones

NRC publication: Ye