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PRAO Radiotelescopes

The search for pulsars and transients, as well as their research within the framework of the BSA-Analytics project, are based on the results of monitoring observations at the antenna of the Large Phased Array (LPA). LPA is located in Pushchino of Moscow region at the Pushchino Radio Astronomy Observatory of the Astro Space Center of Lebedev Physical Institute of the Russian Academy of Sciences (PRAO ASC LPI).

LPA is the world's largest array in the meter wavelength range.range. Its name stands for Large Phased Array.
There are two ways of translating it in the scientific literature:

BSA - Big Scanning Array,
LPA - Large Phased Array.

The name BSA is not quite true, but it's convenient, because its abbreviation matches the Russian version.
The name LPA is more correct because it reflects the essence of the antennatenna: this is an antenna array that collects the signal in phase.

There are three radio telescopes at the Pushchino Observatory:

LPA - Large Phased Array,
DKR-1000 - Wide-Band Cross-type Radio Telescope 1 km long,
RT-22 - Radio Telescope with a bowl diameter of 22 m.

Radio telescopes of the Pushchino Observatory. Video shooting from a quadcopter Wind of Eternity


Pushchino Radio Astronomy Observatory		A particle of the ashes of the founder of radio astronomy, Grote Reber, is buried in the wall of the observatory.


The main entrance to the observatory		LPA - Large Phased Array


DKR-1000 - Wide-Band Cross-type Radio Telescope		RT-22 - Radio Telescope with a bowl diameter of 22 m

Large Phased Array

The LPA was built in 1974. It consists of 16 384 wave dipoles and covers an area of more than 7 hectares. Initially, the central receiving frequency of the antenna was 102.5 MHz, and the effective area was 20 000 - 25 000 m². After the government sold the LPA's frequency range to commercial entities in the 90s, the antenna was upgraded. The central reception frequency has become 110.25 MHz. At the same time, the effective area decreased to 10 000 - 15 000 m². In 2009, the observatory received a grant under the Space Weather program. He made it possible to significantly upgrade the antenna. The main stage of modernization took place in 2010-2012. The cable system was rearranged, digital receivers were created, and the Butler matrices were replaced. New amplifiers with one input and four independent outputs were supplied. This made it possible to create four independent radio telescopes based on a single antenna of the BSA FIAN.

LPA-1 Radio Telescope

LPA-1 is an upgraded version of the antenna for pulsar observations.

It has a controlled diagram – the rays are directed to the desired area of the sky;
You can use from one to eight consecutive beams;
It is possible to receive up to 512 frequency channels in the standard mode;
The effective area has increased by 3-4 times compared to the old version of the telescope (LPA-2);
LPA-1 is used only for pulsar observations (its recorder is designed for this);
Since 2019, all the time on the telescope, free from individual observations, is used for monitoring.

Monitoring observations at LPA-1:

128 frequency channels + 1 total;
8 beams selected at site N4 (from +86.61^o to +52.85^o)
tresolution=0.003072 ~ 3 msec

LPA-2 Radio Telescope

LPA-2 is an old version of the radio telescope, it was turned off as soon as LPA-1 was launched.

In this variant, the antenna had 512 beams, formally overlapping declinations from about -28^o to +88^o. A digital pulsar receiver could connect to any of these beams. In reality, declinations from -5^about to about +75^about were used, because below -5^about there was high interference and small effective area, and above +75^about It took a lot of time to observe the source.

LPA-3 Radio Telescope

LPA-3 is a multipath radio telescope for monitoring programs.

It has a stationary diagram — the positions of its rays do not change;
It has three recorders working with different sites in the sky.:
- recorder 0 — area N0 - 4 modules of 8 beams (from +55.22° to +42.53°);
- recorder 1 — area N1 - 6 modules of 8 beams (from +42.26° to +21.40°);
- Recorder 2 — area N2 - 6 modules of 8 beams (from +20.64° to -8.04°).
It can receive up to 32 frequency channels;
LPA-3 is used only for monitoring, i.e. for round-the-clock observations simultaneously in all 128 beams;
Recording is performed in two modes - «short data» and «long data».
Short data has been recorded since 2012, and long data has been recorded since 2014.

Monitoring observations at LPA-3 - «short data»:

6 frequency channels + 1 total;
6 modules of 8 beams (for area N1, N2);
4 modules of 8 beams each (for area N0);
tresolution=0.09999424 sec ~ 100 ms

Monitoring observations at LPA-3 - «long data»:

32 frequency channels + 1 total;
6 modules of 8 beams (for area N1, N2);
4 modules of 8 beams each (for area N0);
tresolution=0.0124928 sec ~ 12.5 ms