On December 6th and 7th, 1993 an IRAM User Meeting took place. It was attended by roughly 30 guest observers at the IRAM telescopes and in addition by many of the local staff members. IRAM provided an update on the current telescope status and planned developments.
For the 30m telescope, W. Wild reported significant progress in the
adjustment of the surface panels, resulting in a reduction of the
rms-value by about 
inferred from recent holography, reported by
Dave Morris. Beam efficiency measurements are still pending, but
expectations are that the performance of the telescope at 1mm and at
0.8 mm should significantly be improved. A key item of discussion in
connection with the 30m telescope concerned the alignment of different
receivers and the issue of remote tuning. Bernard Lazareff gave an
outline of the mid-term instrumentation plans. James Lamb filled in
details of the present receiver construction planning. Brief status
reports were given by Karl Schuster and Roberto Neri on the multibeam
heterodyne and bolometer array, respectively. As these two projects
are still in an early stage, and as both will require substantial new
software developments, an invitation was issued to other laboratories
and research groups who want to participate. In connection with the
development of arrays but also in connection with the extension plans
for the Plateau de Bure interferometer (see below) the need for a new
correlator development arises. Marc Torres briefed the audience on the
current status of chip developments which will in the end determine
what IRAM can do.
Stephane Guilloteau described in some detail the experience from more than 6 months of operations with four antennas on Plateau de Bure, and explained the status of preparations both for an extension of the tracks and for the number of antennas from 4 to 5. The latter is still only a hope which could, however, soon become reality. As part of the preparatory work, IRAM has developed in close cooperation with an industrial firm a new kind of all-aluminium panels, and Dietmar Plathner presented to the audience the second prototype that has been manufactured and is now undergoing detailed testing.
In his talk, Stephane Guilloteau had included some remarks about the status of data reduction and data reduction software. This triggered a rather intense discussion about IRAM's software support to outside groups. In particular, the issue of UNIX versus VMS as the operating system came up. A show of hands indicated that in the community VMS is still widely in use whereas both IRAM and the Grenoble Observatory have focussed their efforts on UNIX. Since this was not the first time that this issue came up, it is clear that the situation must carefully be reviewed, and IRAM agreed to do this in close collaboration with the Grenoble observatory.
In this context it is very important that members from the User Community make known to IRAM what specific software problems they encountered during observations or during data reduction. This is a standing invitation!
The second day of the User Meeting allowed for a fair number of short contributions from guest observers which highlighted the wide variety of topics that are tackled with the 30m telescope and with the interferometer, respectively. Prior to these contributions a whole session was devoted to a status report on the key project which is carried out at the 30m telescope since the fall of 1992. Edith Falgarone and Jürgen Stutzki briefed the audience on behalf of the key project team and showed that the observations have advanced well but certainly not at the speed that had originally been hoped for. Weather is the primary cause for delays. Given this learning experience and the actual state of the project, it is premature to reach any conclusions as to whether or not the scheme of key projects should be continued in the future or not.
Michael GREWING