Memorandum of Understanding

concerning VLBI observations at 3mm wavelength

Version 1.0 / 21 August 2003

The Directors of undersigned radio observatories,

Recognising that the scientific potential of mm-wavelength Very Long Baseline Interferometry (VLBI) can be greatly enhanced using the improved sensitivity arising from joint operation of the U.S. Very Long Baseline Array and sensitive mm-wavelength antennas agree the following:

1)To set aside blocks of observing time at the observatories, reserved for 3mm wavelength VLBI observations.
The periods will be agreed at least 6 months in advance (tentative dates for 2004 are April 16-21 and October 8-13)
The initial length of the periods will be 5 days
Time not scheduled for such observations will revert to individual observatory use
2)To distribute a Call for Proposals for use of the reserved time for 3mm-wavelength VLBI experiments.
The deadlines for receipt of proposals will coincide with those currently used for cm- wavelength VLBI (1st October and 1st February).
The Call is open to all members of the astronomical community.
Technical and administrative information will be made available to proposers via a WWW page (
3)Proposals will be sent both to NRAO and to a European mm-VLBI Scheduler (E. Ros at MPIfR has been nominated for this role). The VLBA and European mm -VLBI Schedulers will jointly supervise the proposal review process and decide which proposals are to be observed in each session.
Proposals will be distributed to a designated person at each participating observatory for review; the review process at each observatory can be decided by that observatory's management.
Each observatory will provide the results of its review process to the Schedulers no later than 12 weeks after the proposal deadline
The Schedulers will decide which proposals are to be observed on the basis of the reviews by all the observatories.
The participating observatories accept the scheduling decisions of the Schedulers.
4)The proposers of scheduled projects will be notified by the Schedulers. Proposers may construct their own observing schedules (which must conform to rigorous advertised guidelines to ensure the successful operation of the various antennas) or they may seek assistance from observatory staff designated by the Schedulers.
Schedules must be submitted by an advertised deadline, normally 3-4 weeks before the start of the observing session.
For observing and tape-logistical reasons, the individual project schedules will normally be integrated into longer blocks by observatory staff designated by the Schedulers before distribution to the observatories.
Calibration sources may also be inserted in gaps within the integrated schedule to assist all observers with their analysis. Data from all such observations will be made public after correlation.
5)Data will be correlated at the MPIfR MK4 correlator in Bonn, and provided to the proposer in u,v-FITS format.
Other correlators may be requested in the proposal if there is a good technical reason. This may, however, cause logistical complications and lead to scheduling delays.
The proposers have exclusive use of the data for a proprietary period of 12 months after receipt of the data from MPIfR.
MPIfR will release the recorded tapes/disks after correlation in a timely manner.
6)The operation of this agreement will be reviewed by the Observatory Managements periodically, and initially after the first two observing periods.

Initially, the following Observatories are party to this Memorandum:
-The US National Radio Astronomy Observatory (for the VLBA)
-IRAM -Institute for mm Radio Astronomy (for Pico Veleta and Plateau de Bure)
-The Max-Planck-Institut für Radioastronomie (for Effelsberg)
-The Onsala Space Observatory (for their 20m antenna)
-Metsähovi Radio Observatory (for their 14m antenna)

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