Sky surveys are a basic research tool of astronomy. Radio sky surveys
have never been
stopped since radio astronomy was born. Before 1990's, a sky survey with large
area could be done either by a radio Schmidt telescope such as 6C survey
(Baldwin J.E. et al. 1985), or by a transit
instrument such as NCT
(Ficara A. et al. 1985).
But recently, large radio telescopes begin to perform large sky area survey, for
examples, the WENSS
(De Bruyn 1995)
and NVSS
(Condon et al. 1993)
are being carried out by WSRT and VLA respectively.
The Miyun 232 MHz survey is a moderately deep meter-wave survey. Its working frequency is in between that of 6C and that of B3 among the tens radio sky surveys. Its sensitivity, resolution and width of the primary beam are comparable to those of MRAO and DRAO telescopes (Veidt 1985). The Miyun aperture synthesis system (Wang 1984), working at 232 MHz, consists of an E-W array of 28 dishes, each of 9m in diameter. This array is divided into sub-array A (16 dishes in the center part) and sub-array B (12 dishes, 6 dishes at the east of the sub-array A, and the other 6 dishes at west of the sub-array A). The configuration of the telescope can be found in a paper written by Zhang et al. (1993, hereafter Paper I), and the characteristics of the array are summarized in Table 1 (click here). For details about the telescope, refer to Beijing Observatory Meter-Wave Radio Group (1985).
Table 1: The characteristics of the MSRT