Abstract
The Nobeyama Radioheliograph
is a radio interferometer dedicated to
solar observations at 17
GHz. Its imaging performance is concisely described on the basis of the
correlator outputs.
Antenna-based errors are removed by a self-calibration method. Possible
causes of
correlator-based errors have been considered, respectively. Among them,
the important factors
are: (1) unequal bandpass characteristics, (2) antenna pointing errors,
(3) delay errors, and (4)
noise at correlator outputs. The expected dynamic range of synthesized
snap-shot images is 30
dB based on these correlator-based errors. However, the actual images
have a 25 dB dynamic
range, which may be mostly due to the image-restoration procedure
currently adopted.