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Obtaining Observing Time on the VLA

How to Propose

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 online Proposal Submission Tool (PST) available via the NRAO Interactive Service web page, at https://my.nrao.edu/. The online tool permits the detailed construction of a cover sheet specifying the requested observations, using a set of online forms, and uploading of a PDF format scientific justification to accompany the cover information. More specific info on using the online tool, and policies related to proposal types, scientific justification page limits, etc..., can be found in the NRAO User Portal and Proposal Submission Guide. VLA-specific details, including capabilities offered for the next proposal deadline, can be found in the Offered VLA Capabilities chapter of the current VLA Observational Status Summary (OSS) document. For further information on observing at the VLA, including information on radio frequency interference (RFI), 8/3 bit Attenuation and Setups, and pre-submission checklists for Scheduling Blocks and instrument configurations, please see the Guide to Observing with the VLA.

It is also possible to obtain VLA observing time by proposing to NASA missions, under cooperation agreements established between NRAO and those missions. Such programs exist for the Chandra, Fermi, Swift and HST missions. Astronomers interested in those joint programs should consult the relevant mission proposal calls for more information.

Note that it is possible to search cover sheets of proposals previously approved for time using the Proposal Finder Tool (PFT).


Students planning to use the VLA for their Ph.D. dissertation must submit a Plan of Dissertation Research of no more than 1000 words with their first proposal. This plan can be referred to in later proposals. At a minimum, the plan should contain a thesis time line and an estimate of the level of VLA resources needed. The plan provides some assurance against a dissertation being impaired by an adverse review of a proposal when the full scope of the thesis is not seen. The plan can be submitted via NRAO Interactive Services. Also see the Plan of Dissertation Research subsection of the NRAO User Portal and Proposal Submission Guide for more details. Students are reminded to submit their plan comfortably in advance of the proposal deadline. New thesis plans must be in PDF format to enable science reviewers to easily access the plans. Students who have not yet graduated, but have active plans on file, should consider updating those plans to a PDF format if they are not already in that form.


Time on the VLA is scheduled on a 6-month semester basis. Semester A observations typically take place February through July and have an August 1 proposal deadline in the previous year; Semester B observations, with deadline February 1, take place from August through January. If the deadline falls on a weekend it is extended to the next working day. The call for proposals, which typically goes out 3–4 weeks prior to the deadline, includes an overview of upcoming deadlines and VLA configurations.

For details on the evaluation of submitted proposals we refer to the NRAO Proposal Evaluation/Time Allocation page. Because of competition, even highly ranked proposals are not guaranteed to receive observing time. This is particularly true for proposals that concentrate on objects in the LST ranges occupied by popular targets such as the Galactic Center or Virgo. Daytime VLA observing will also continue to be limited by ongoing testing and maintenance activities; for more information, see the section on Scheduling Considerations in this document.

Director's Discretionary Time

It is also possible to propose for Director's Discretionary Time (DDT). DDT is reserved for Targets of Opportunity and for Exploratory Time. DDT proposals may be submitted at any time with the understanding that they should only request for the current and, maybe, the next upcoming array configuration. The DDT proposals must be submitted through the PST. DDT proposals are reviewed by Observatory scientific staff on the basis of the proposals' scientific merit, conflict status, LST pressure, and technical feasibility.