New versions of Ephemerides of Planets and the Moon, EPM2021 and EPM2021H, are available.

The Institute of Applied Astronomy and the National Commission on Space Activities of Argentina (CONAE) successfully conducted intercontinental bistatic radar observations of the Moon. The observations involved the 35-meter antenna (DSA 3) of the European Space Tracking Network (ESTRACK) at Malargüe station in Argentina and the 13.2-meter radio telescope (RT-13) at Svetloe Radio Astronomy Observatory of the Russian VLBI network (Quasar).

The DSA 3 antenna irradiated the Archimedes crater in the east of Mare Imbrium with a signal at 7190 MHz (4.2 cm) and at the same time the RT-13 antenna received echoes reflected from the Moon. As a result of the observations, radar images of the lunar surface were obtained with a spatial resolution of about 300 meters.

Radar observations are one of the most effective methods of Earth-based remote sensing of the Moon, allowing high spatial resolution mapping and exploration of surface and subsurface physical properties. This data can be used to select landing sites for spacecraft, prospecting, and mining, which is especially important due to the increased interest of many countries in lunar exploration.

The IAA RAS carried out radar observations of the near-Earth object 2020 SO, discovered on September 17, 2020 by Pan-STARRS 1 telescope at the Haleakala Observatory in Hawaii. Its Earth-like orbit and low relative velocity suggest that the object may be of artificial origin, being the Surveyor 2 Centaur rocket booster launched on September 20, 1966. In the period from November 2020 to March 2021 this object will approach the Earth twice within one lunar distance of Earth.

As part of international cooperation, the Svetloe radio astronomy observatory received signals from the 70-meter Goldstone Solar System Radar (USA) reflected from 2020 SO using the 32-meter radio telescope RT-32. Joint radar observations were carried out on November 30, while the object was in the visibility window of two antennas at about 200 thousand km from the Earth.

As a result of the observations the rotation period of 2020 SO was determinedto be only 9.5 seconds, which corresponds to the photometric observations. Obtained range-Doppler radar images confirm that the object has an elongated shape with a length of about 10 meters and a width of about 3 meters. The radar albedo of 2020 SO was also determined, with a value of about 1. This result confirms that the surface of the object has a high reflectivity in the radio range, typical for metals.

The 2nd Russian-Chinese working group "IAA-RAS & NAOC-CAS Collaborating Researches & Workshops" will be held in St.Petersburg on October 7-9, 2019 to discuss joint research in the field of astrometry, space geodesy, astrophysics and radio astronomy.

Weather data archive for the three radioobservatories of IAA RAS is available.