Proposal Preparation, Submission, & Review

Observing time on the VLBA is scheduled on a semester basis, with each semester lasting six months. Proposal deadlines are February 1 and August 1, with the February 1 proposal deadline nominally covering time to be scheduled during the following August through January, and the August 1 deadline covering time to be scheduled from February through July. Time can be requested over multiple semesters if scientifically justified.

A Call for Proposals is published approximately four weeks in advance of each semester submission deadline. Proposals must be prepared and submitted using the NRAO Proposal Submission Tool (PST), available via NRAO Interactive Services.  Observing proposals may specify the VLBA alone, or the various extended arrays. For more proposal preparation related details, we refer to the Guide to Proposing for the VLBA. Proposal preparation and submission questions may be submitted to the Proposing Department of the NRAO helpdesk. A "Guide to Using the VLBA" is also available, aimed specifically at inexperienced users but also useful to fill in knowledge gaps for more experienced observers.

Submitted proposals are reviewed by a Science Review Panel (SRP) in relevant subdisciplines (e.g., solar system, stellar, Galactic, extragalactic, etc.). The SRP's comments and rating are strongly advisory to the Time Allocation Committee (TAC), and the comments of both groups are passed on to the proposers soon after each semi-annual meeting of the TAC, and prior to the next proposal submission deadline. A detailed description of the time allocation process is available.

Approved programs are then scheduled by the VLBA scheduling officers. Questions about telescope time allocation may be sent to the VLBA Scheduling Department in the NRAO helpdesk or to the VLBA scheduling officers at schedsoc@nrao.edu.       

The VLBA SCHED program (Walker 2011) can be used to determine the Greenwich Sidereal Time range during which the VLBI target sources are visible at various stations. This program can also be used to evaluate the u-v plane coverage and synthesized beams provided by the selected array.

An accurate source position service is available to obtain positions accurate enough for correlation. This should be requested simultaneously with the proposal, if not earlier. 

Connect with NRAO

The National Radio Astronomy Observatory and Green Bank Observatory are facilities of the U.S. National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

Founded in 1956, the NRAO provides state-of-the-art radio telescope facilities for use by the international scientific community. NRAO telescopes are open to all astronomers regardless of institutional or national affiliation. Observing time on NRAO telescopes is available on a competitive basis to qualified scientists after evaluation of research proposals on the basis of scientific merit, the capability of the instruments to do the work, and the availability of the telescope during the requested time. NRAO also provides both formal and informal programs in education and public outreach for teachers, students, the general public, and the media.

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