Oh Radio Observations of Comets P/Brorsen-Metcalf (1989o), Okazaki-Levy-Rudenko (1989r), Aarseth-Brewington (1989a1), and Austin (1989c1) at the Nancay Radio Telescope

The 1667 MHz and 1665 MHz transitions of the OH radical were recently monitored in several comets with the Nangay radio telescope: PBrorsen-Metcalf (1989o) (August 4 to October 31, 1989), Okazaki-Levy-Rudenko (1989r) (October 3 to December 2, 1989), Aarseth-Brewington (1989a1) (December 8 to 30, 1989) and Austin (1989cl) (February 15 to June 14, 1990). We present gas expansion velocities measurements obtained from the analysis of the line shapes and discuss the long term variations of the water production rate, as measured from the OH radio lines. On October 13, 1989, we fortuitously-observed the occultation of A. background source by comet Okazaki-Levy-Rudenko (1989r). A preliminary report of this obse*vation is given. Further analysis of the data is continuing.