Observing time on the VLA is available to all researchers, regardless of nationality or location of institution. There are no quotas or reserved blocks of time. The allocation of observing time on the VLA is based upon the submission of a VLA Observing Proposal using the on-line VLA proposal tool available via http://www.vla.nrao.edu/astro/prop/vlapst/ . Note that proposals using the old VLA LATEX form are no longer accepted! The on-line tool permits the detailed construction of a cover sheet specifying the requested observations, using a set of on-line forms, and uploading of a pdf-format scientific and technical justification to accompany the cover information.
Students planning to use the VLA for their Ph.D. dissertation may have a problem in that such dissertations are frequently composed of pieces of several short proposals which may not be suitable for combining into a single proposal for refereeing purposes. In this case, we shall accept, one per student, a `Plan of Dissertation Research', of no more than 1000 words, at the time of the first proposal of the series, and which can be referred to in later proposals. The plan of dissertation research should be e-mailed to schedsoc@nrao.edu. This provides some assurance against a dissertation being seriously damaged by adverse referee comments on one component proposal, when the referees may not see the whole picture. This facility is offered to students for which VLA observations are the most important component of their planned dissertations.
The VLA is scheduled on a trimester basis, with each trimester lasting four months. The proposal deadline for a particular configuration is 5PM (1700), Eastern Time on the 1st of February, June, or October which precedes the beginning of that configuration by three months or more. (If the first of the month falls on a Saturday or Sunday, the deadline is advanced to the next Monday.) As stated in Section 2, the traditional VLA configuration rotation is expected to be modified over the next several years, during EVLA commissioning. It is not necessary to submit a proposal at the last possible deadline for a particular configuration, since all proposals will be refereed immediately following the deadline of submission, regardless of the configuration requested. Early submissions - more than one deadline in advance of the relevant configuration deadline - will benefit from referee feedback and the opportunity for revision and additional review if warranted.
All proposals are externally refereed by several experts in relevant subdisciplines (e.g. solar system, stellar, galactic, extragalactic, etc.). The referees' comments and rating are strongly advisory to the VLA/VLBA Proposal Selection Committee, and the comments of both groups are passed on to the proposers soon after each meeting of the committee (three times yearly) and prior to the next proposal submission deadline. See http://www.aoc.nrao.edu/epo/ad/scheduling/shtml for a detailed description of the time allocation process.
A special refereeing process has been established for proposals requesting an unusually large amount of time - 200 hours or more for any individual NRAO telescope (or combinations thereof). Details of this process can be found via http://www.vla.nrao.edu/astro/prop/largeprop/.
Scheduling the telescope is a non-exact science, and because of competition, even highly rated proposals are not guaranteed to receive observing time. This is particularly true for programs that concentrate on objects in the LST ranges occupied by popular targets such as the Galactic Center or the Virgo cluster.