All in all, the weather conditions have been very good at the Plateau de Bure last winter with long periods of excellent phase stability and low atmospheric opacity. The interferometer recorded a 50-60% observing efficiency in January and February but only a very low efficiency of 30% in March. To optimize the observing efficiency with respect to the sun avoidance constraints of A-rated projects and due to some delays with the installation of the proto-type NGRx at the beginning of the last winter semester, the configuration schedule of the interferometer was slightly adjusted.
The array was moved to the most extended new configuration A (including stations E68 and N46) in mid January, moved to the new B configuration in mid February and to the C configuration in the second half of March. Because of the weather conditions, the array was rearranged to the most compact configuration (D) at the end of April. The Global VLBI observations from May 4 to 8, 2006 could not be joined by the Plateau de Bure array because of the irreparable breakdown of the CNRS maser 5 days before the start of the VLBI session.
Most of the A-rated projects could be completed before the end of the winter period, although a few projects requesting the D configuration had to be moved into the current summer period. We have also invested observing time on a number of B projects, and even on a few targets of opportunity. Since last December, a total of 57 different projects has successfully been scheduled for observations. Concerning projects that have been started shortly before the end of the winter period, we plan to bring these to completion in the next few months. A few deep integration and low-resolution observations of sources in the Orion-Taurus region had to be suspended because of sun avoidance constraints and are now deferred to the end of the summer semester.
Finally, we would like to remind users of the Plateau de Bure Interferometer that B-rated summer proposals which were not started by the proposal deadline, should be resubmitted. Investigators, who would like to check the status of their project, may consult the interferometer schedule on the Web at ../IRAMFR/PDB/ongoing.html.