Aleksander Stanislavsky, Artem Koval, Aleksander Konovalenko, Eduard Abranin
The broadband analog-digital heliograph based on the UTR-2 radio telescope is
described in detail. This device operates by employing the parallel-series
principle when five equi-spaced array pattern beams which scan the given radio
source (e.g. solar corona) are simultaneously shaped. As a result, the obtained
image presents a frame of 5 x 8 pixels with the space resolution 25' x 25' at
25 MHz. Each pixel corresponds to the signal from the appropriate pattern beam.
The most essential heliograph component is its phase shift module for fast sky
scanning by pencil-shape antenna beams. Its design, as well as its switched
cable lengths calculation procedure, are presented, too. Each heliogram is
formed in the actual heliograph just by using this phase shifter. Every pixel
of a signal received from the corresponding antenna pattern beam is the
cross-correlation dynamic spectrum (time-frequency-intensity) measured in real
time with the digital spectrum processor. This new generation heliograph gives
the solar corona images in the frequency range 8-32 MHz with the frequency
resolution 4 kHz, time resolution to 1 ms, and dynamic range about 90 dB. The
heliographic observations of radio sources and solar corona made in summer of
2010 are demonstrated as examples.
View original:
http://arxiv.org/abs/1112.1044
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