Solar
Receiver Complex
![sunbar2.gif (2714 bytes)](gif/sunbar2.gif)
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)](gif/ratan2.gif)
-
Antenna
RATAN-600
-
Receivers-> Panoramic Analyser of Spectrum
-
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 ).
Common
plan of telescope |
Modes of operation
|
-
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 -41Ï 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 ]