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Paper: Correcting Some DRAO Synthesis Telescope Wide-Field Imaging Problems
Volume: 101, Astronomical Data Analysis Software and Systems V
Page: 211
Authors: Willis, A. G.; Higgs, L. A.
Abstract: The small diameter antennas of the DRAO Synthesis Telescope give this instrument a very wide field of view (103 arcmin FWHM at 21 cm wavelength and 318 arcmin at 74 cm wavelength). Consequently the telescope has recently begun a systematic survey of a large region of the galactic plane. However, due to the wide field of view and a high sidelobe level, the antennas often detect a bright source such as Cygnus A, Cass A, or Taurus A at large distances from the field center. Grating rings from these sources often pass through the central part of the image, degrading that part of the image which the astronomer is interested in. Because of instrumental irregularities such as pointing errors and phase reversals within sidelobes, it is not possible to accurately remove the influence of these sources by standard CLEAN or self-calibration techniques. We describe a procedure which, despite its relative simplicity, is remarkably successful at removing the effects of these sources. We call this procedure MODCAL, for MODel CALibration.
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