NED object is MESSIER 033; Reference is 1978A&A....62...51V

   Fig. 1. Contour map of M33 at 4850 MHz. One contour interval corresponds to
 10 mK in T_b_. Contours 1, 4 and 7 are drawn thick; hatched contours enclose
 minima. The position of the optical center is indicated with a plus. Open
 plusses are at positions of reference stars. The half-power beamwidth of
 2.6arcmin is shown in the lower lefthand corner.