In abstract book of XXIV URSI General Assembly in Kyoto, Japan, August
25-September 2, 1993
Holography equipment, techniques and
their applications at RATAN-600 radio telescope
are described in [1]. In this paper we
consider surface holography testing of single RATAN-600 panels.
Each of 1000 RATAN-600 full
steerable elements (2x7.5 m size) can be easily scanned under co
puter control by azimuth and elevation angles. For hologram recording we
use a specially designed Ryle type holography receiver [2]
in the radio telescope focus and Gann oscillator in RATAN-600 near
region. It takes about 1.5 hr measure a two-dimensional
holog ram of a single panel and few minutes
more to reconstruct an aperture field distribution usng
FFT algorithm.
Simulation of a holography reconstruction
process for a single panel in close to real experiment conditions is given
in the paper.
Fig.l. shows the reconstructed aperture phase
and amplitude of RATAN-600 panel with number 669. A test plate
of 85x20 cm size and 3 mm(X/4) thick primarily installed on the panel surface
(Fig.la) can be clearly distinguished in the reconstructed
aperture phase (Fig. 1b). The contribution of Fresnel
effects influencing mainly aperture field distribution
(Fig.1c)is discussed. We estimate accuracy of this method
to be about 100 pm during night time with resolution
up to 20x20 cm.
Fig. 1. Reconstructed surface of the
single RATAN-600 panel. a - primarely installed test plate on the
panel surface, b - reconstructed surface phase, c- reconstructed
surface amplitude map
References
[1]V.Khaikin,Proceedings of IAU Colloquium 140,Hakone,Japan,l992
[2]V.Khaikin,A.Yaremenko. Proceedings of
International Workshop on Holography in N.Arkhyz, Russia, pp.82-84,
1992..