Data Access

The online archive contains all VLA data since observing started in 1976, and also serves the user community with EVLA data. The entire archive is now on disk, and is available via the Archive Access Tool (AAT) at http://science.nrao.edu/facilities/evla/archive/evla/ . This interface provides a basic data retrieval tool if you know the program code of your observations. It also provides an advanced query tool which enables searches based on a large number of user-specified criteria. Data can be downloaded via standard ftp protocols and via shipment of physical harddisks (see https://science.nrao.edu/facilities/evla/data-archive/data-shipment for the disk shipment policy). With the exception of some rapid response and large proposals, (E)VLA data associated with a given proposal normally are restricted to proprietary use by the proposing team for a period of 12 months from the date of the last observation in a proposal (Note: data taken more than 12 months previously may still be proprietary, if additional data for the same proposal have been taken within the last 12 months). Proprietary data may be downloaded by the observing team by logging in to the AAT with the my.nrao.edu/PST user account or by making use of the project key (see The Observations and Remote Observing).

Data are stored in the archive in the Science Data Model (SDM) format that will be used by both the EVLA and ALMA. They are available through the AAT in one of two formats:

- As a CASA Measurement Set.
- In UVFITS format, which can be read by either AIPS or CASA.

The raw SDM format will only be available by special request submitted through the NRAO Helpdesk.

Note that some archival data have known problems which, together with the possible fix, are listed at http://www.vla.nrao.edu/astro/archive/issues/ .

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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