The stop of all the observing activities at the interferometer, which was decided in December 1999 (see Newsletter 43), is still valid.
However, efforts are being made to clarify the conditions under which observations can be resumed after the summer maintenance period. We are aiming at mid-October to restart regular observing sessions.
In the meantime top priority is given to the technical maintenance of the interferometer which started on July 20th after clarifying the related safety aspects. Minor problems and a few potential causes of malfunction of the instrument after the long shutdown have already been identified. All receivers have recently been cooled down again and their performance verified. The antennas have also been tested independently in single-dish mode and all together in interferometric mode.
Further priority will be given to the installation of the new six antenna correlator. According to the planning, about two weeks are required this September to install and test the new correlator.
As a second priority item, some work will be carried out on the insulation of the mount of antenna 6, but major items like the assembly of the reflector have been deferred to 2001.
As stated above, all the regular observing activities are still stopped. Some astronomical tests which are needed to diagnose the state of the instrument have, however, been carried out and will continue as maintenance work progresses. According to the current plans, the execution of proposals submitted for the summer period will not start before October, at the earliest.
Therefore, all of the summer proposals, including A-rated ones, will have to be resubmitted either for the coming winter session, or for the next summer session, unless opportunities still come up in October and before November 15th. The principal investigators of A-rated proposals will be kept informed in the weeks to come about any new development concerning the scheduling of their projects.