Antenna RATAN-600 and techniques of observations

Antenna RATAN-600

Radio Astronomical Telescope Academy Nauk (science) of Russia is one of the two big telescope of Special Astrophysical Observatory. BTA and RATAN-600 are largest optical and radio telescopes in Russia.

RATAN has seen 'first light' from source PKS 0521-36 12 July 1974 . Since more 50000 observations were caried out in continuum. Main advantage of the telescope is multi-frequiency (1 - 31 cm wavelength) and high bright temperature sensitivity.

Antenna of RATAN radio telescope consist of 576-m circle of 895 elements (2 x 11.5 m), which could use as four independent sectors (225 elements) of that reflector (named: North, South, West and East). Four different feed-cabines (N1,2,3,5) with secondary mirrors could simulteniously collect radio emission from these four sectors and be used in programs of Continuum , Spectral and Solar observations.
In 1999 feed-cabine #5 will use for mixed continuum/spectral programs.
In 1999 feed-cabine #6 will use for mixed continuum/solar programs.
With central rail-way rotation circle the feed-cabines could be move in any of 12 fixed azimiths. But in 1999 only azimuths 0, 30, 180 and 270o can be used in observations.

In 1985 a new conical mirror and feed-cabine N6 was firstly used. That feed-cabine aloows to collect radio emission from whole circle, but range of source declinations limited in this regime the zone of zenith distance z=+-6o (or Dec: 38-49o).

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View of RATAN-600 from ratan.exe by S.Trushkin

General view of telescope. Click on left mouse button to see the short describing of the elements of RATAN-600.

Geographic coordinates of the RATAN center, as measured with astrometric observations in 1968 Juanary:
latitude (phi) 43o 49' 52".75±0".16
longitude -02h46m22.1s or -41 35' 31".5
hight from sea level 970 m

A0 H = (90 - phi) + delta = 46o10'07".25 + delta

A180lc H = -(90 - phi) + delta = -46o10'07".25 + delta

A180uc H = (90 + phi) - delta = 133o49'52".75 - delta

Closing angles by mountains:
Azimuth Hmax Directions
0o 2o16'52" in North
90o 2o07'00" in East
180o 3o19'30" in South
270o 2o39'00" in West

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Techniques of observations

  1. Usualy the transit regime of source through unmoving direction diagram (beam) of telescope. That regime is fitted for big list of sources or for survey on fixed elevation.
  2. Regime of 'unmoved focus' with one sector is fitted for massive observations of sources in range of nearby declinations: 2-3o for DEC = 0 and 10o - for declination: -30o. In this case feed-cabine became in the same position, thus no movement or ajustment of horizon. Accuracy of determination of RA and DEC improves to 3-10". Affective area of one sector is near 1000 m in square.
  3. Since of 1996 the current regime of 'sliding' with effective time of collection of 60-100 second. If you know coordinates of object you could decrease threshold of determination of radio emission. his regime could use anly with North or South sectors.
  4. Regime "Zenith" is observation with feed-cabine N6 and whole circle, but is not in the plan of 1997.
  5. Regime "Atmosphere" is vertical cross-cuts for detrermination absorbtion in atmosphere, it needs only 1-2 cross-cuts-removing of antenna from 5 to 30o.
Trushkin, LabRAO SAO 1999

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flat_mirror flat_mirror center of RATAN-600 feed-cabine N1 for continuum observations feed-cabine N2 for spectral observations feed-cabine N3 for solar observations feed-cabine N6 for whole circle observations feed-cabine #5 This is Northern Sector This is Western sector this is Eastern sector This is South sector This is center numbers of main sectors this is azimuth of antenna