Semester 96B operations


As PATT wanted the Semester 96A session to be devoted solely to K-Band ( 22 GHz ) observations, no time was given as a part of the allocation for that semester to the first phase of a pulsar proper motion experiment at L-Band (1.4 GHz), even though it had been highly rated. However, as the experiment involved only the Lovell and Cambridge telescopes, it was suggested that the Jodrell Bank proposers should seek to carry out the observations during the summer maintenance and development period. This was in fact done.

Both the Cambridge (being 'frequency agile') and the Lovell telescopes had already been equipped with L-Band receivers and it was only necessary to make some minor alterations to the electronic systems to incorporate the Lovell telescope into MERLIN. A few hours were required to measure and check a number of system parameters and to carry out the limited system calibration required. Approximately twelve days of MERLIN observations were obtained during a three week period, the observation time being shared with a pulsar timing experiment after the first week and also with Lovell telescope painting and engineering work during the later stages.

As telescopes became available following the summer maintenance and engineering work, they were equipped with 5GHz receivers, so that by mid-October, it was possible to carry out those Semester 96B programmes not requiring the full complement of telescopes, in particular a programme of astrometric observations of highly variable stars. Radio emission has already been detected from an increased number of these stars.

It had been expected that all of the MERLIN telescopes would only become available for the MERLIN Semester 96B PATT approved programme during the second week of November due to the engineering work and the requirements ofVLBI observations. However, as a result of a rescheduling of the VLBI session, all the telescopes became available at the beginning, enabling a few observations, originally given time with a reduced MERLIN system (without Mk2) to be scheduled with a full complement of telescopes. Unfortunately, very windy weather at the beginning of November prevented the maximum benefit resulting from this rescheduling as only an occasional observation was possible during the first week. Since then, however, PATT approved observations have been going well.


wlm@ast.cam.ac.uk