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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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  -41о 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 
-   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.
 -  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.
 
 -  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.
 -  Regime "Zenith" is observation with feed-cabine N6 and whole
circle, but is not in the plan of 1997.
 -  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, satr@sao.ru  LabRAO SAO  1999 
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