Solar Receiver Complex

sunbar2.gif (2714 bytes)

        Beginning from the May of the 1997 we started to  publish our daily solar radio observations at  RATAN-600 radiotelescope.
The RATAN-600  [Brief history and description]   radio telescope is one of two main instruments of Special Astrophysical Observatory of Russian Academy of Sciences.

ratan2.gif (91963 bytes)

globul2a.gif (67 bytes)Antenna RATAN-600
globul2a.gif (67 bytes) Receivers-> Panoramic Analyser of Spectrum
globul2a.gif (67 bytes) Methods of observations->Periscope System: South Sector+Flat Mirror
Our observations are doing with a  high  spatial,  one  - dimensional resolution scan near UT 9-00 at 30-40 wavelengths  in the range from 1.67 cm up to 32 cm  with  left  (LCP)  and  right (RCP) circular polarization with diagram sizes in accordance with the next formulae:

Qhorizontal (arcsec)= 0.85 *l (mm)

Qvertical (arcmin)= 0.75*l (mm)


 The southern sector can operate in combination with the flat periscope reflector. It is possible to track a source by moving the secondary mirror along the arc-shaped railway tracks or to perform azimuthal 2D map synthesis 
Panoramic Analyser of Spectrum
  The list of the wavelengths of
        Panoramic Analyzer of Spectrum (PAS) at RATAN-600:
        --------------------------------------------------------
        NN  Wavelength  Horizontal beam  Vertical beam In Usage
        chn.   [cm]        [arcsec]      [arcmin]
        --------------------------------------------------------
        1     1.67          14.2          12.5              -
        2     1.74          14.8          13.0              +
        3     1.83          15.5          13.7              +
        4     1.91          16.2          14.3              +
        5     2.03          17.2          15.2              -
        6     2.10          17.8          15.7              +
        7     2.23          19.0          16.7              +
        8     2.31          19.6          17.3              +
        9     2.52          21.4          18.9              -
        10    2.66          22.6          19.9              +
        11    2.73          23.2          20.5              +
        12    2.89          24.5          21.7              +
        13    3.06          26.0          23.0              +
        14    3.14          26.7          23.5              -
        15    3.21          27.2          24.0              +
        16    3.42          29.0          25.6              +
        17    3.57          30.3          26.8              +
        18    3.74          31.8          28.0              -
        19    3.83          32.5          28.7              +
        20    4.08          34.7          30.6              +
        21    4.31          36.6          32.3              +
        22    4.44          37.7          33.3              -
        23    4.61          39.0          34.5              +
        24    4.93          42.0          37.0              +
        25    5.26          44.7          39.4              -
        26    6.06          51.5          45.4              -
        27    6.52          55.4          49.0              -
        28    7.02          59.6          52.6              +
        29    7.37          62.6          55.2              -
        30    7.59          64.5          57.0              +
        31    8.17          69.5          61.2              +
        32    8.62          73.3          64.6              -
        33    8.95          76.0          67.1              -
        34    9.34          79.4          70.0              +
        35    9.74          82.8          73.0              +
        36    10.17         86.4          76.3              +
        37    10.60         90.1          79.5              -
        38    11.03         93.7          82.7              +
        39    11.49         97.6          86.1              +
        40    12.55        106.6          94.1              -
        41    13.21        112.2          99.0              +
        42    13.95        118.5         104.6              +
        43    14.63        124.3         109.7              +
        44    15.38        130.7         115.3              +
        45    16.12        137.0         121.0              +
        46    17.04        144.8         127.8              -
        47    17.96        152.6         134.7              +
        48    18.94        161.0         142.0              +
        49    28.70        244.0         215.2              +
        50    29.55        251.2         221.6              +
        51    30.45        258.8         228.4              +
        52    31.41        267.0         235.5              +
        --------------------------------------------------------
        +  means the regular usage in the observations
        - means the nonregular usage in the observations

Feed No. 3 the secondary mirror and receiver cabins 


PAS Receivers 

             Dynamic range of the solar registrations is 30 db.   The  maximal accuracy  in  the  measurement  of the polarization degree on the disk is 0.05 % and on the limb is 0.5 %.


Antenna RATAN-600 (from Handbook by Trushkin S.A.)

Antenna of RATAN radio telescope consist of 576-m circle of 895 elements (2 x 11.5 m), which could use as 4 independent sectors (225 elements) of that reflector (named: North, South, West and East). There are tree different feed-cabines (N1,2,3) with secondary mirrors. With central rail-way rotation circle the feed-cabines could move in any of 12 fixed azimiths.

The RATAN-600 can be used for observations in four different modes; these modes are illustrated by the diagram.

(1) It is possible to simultaneously carry out independent observing programs using individual sectors at various discrete azimuths and secondary mirrors on corresponding railway tracks.

Each of these secondary mirrors is a parabolic cylinder with a horizontal axis, 5.5 m x 8 m in size; the horizontal angle over which the main mirror is illuminated is 100 110o . The position of the secondary mirror (the focus) on the railway tracks depends on the elevation above the horizon, which can vary between 0 and 100o and is calculated by a computer at the same time that the coordinates of the elements included in the sector are calculated. Usually, observations using a single sector are carried out at a fixed azimuth (i.e., the source passes through a fixed directivity pattern, with changes from source to source according to the source elevations (20 40 changes per day). In the process, a one-dimensional image of a source is obtained in each observation.
(2) Two-dimensional images of sources can be synthesized by combining the one-dimensional images obtained from a series of successive observations of the same source at different azimuths.
(3) The southern sector can operate in combination with the flat periscope reflector; it then forms a Kraus-type system like those at the University of Ohio or Nansay, France. It will be possible to track a source by moving the secondary mirror along the arc-shaped railway tracks after the work associated with automation is completed.
(4) Finally, using a special conical secondary mirror installed at the center of the RATAN, it is possible to collect radiation from the entire ring while observing near the zenith; the maximum collecting area and resolving power is obtained in this case.

In the end of 1985 a new conical mirror and feed-cabine N6 was firstly used. That feed-cabine allows 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 ).
 
ratan_plan.gif (6746 bytes)Common plan of telescope
fig2-4.jpg (45801 bytes)
Modes of operation

Geographic coordinates of the RATAN center, as measured with astrometric observations in 1968 Juanary:
latitude (phi) 
43o 49' 52".750".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
A180tc 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 


[Solar Group][SAO RAS ]