COEXISTING WITH GLONASS - OBSERVING THE 1612 MHZ HYDROXYL LINE

Transmissions from the GLONASS (Global Navagation Satellite System) satellites have had a disastrous effect on astronomical observations of the 1612 MHz hydroxyl line. At Hartebeesthoek a number of steps were taken to circumvent this problem so that monitoring of OH/IR stars could continue. Techniques were developed for correcting affected spectra; severely degraded spectra were discarded. To monitor the transmissions from the satellites we constructed an independent receiver system. Software was developed for efficiently predicting the best interference-free periods for observations. If the full astrophysical potential of the 1612 MHz line for the study of objects in the Milky Way is to be realized, it will be necessary to maintain a 5 MHz wide interference-free band around the line.