by Davis Murphy last modified Jan 09, 2020 by Heidi Medlin

NRAO operates a complementary, state-of-the-art suite of radio telescope facilities for use by the scientific community, regardless of institutional or national affiliation: the Very Large Array (VLA), the Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA). The following guides scientific users through the process of proposing for and using NRAO observing time.

Call for Proposals

Each NRAO Call for Proposals invites scientists to propose for observing time on one or more of the operational NRAO research facilities. The NRAO issues two Calls per year for proposal submission deadlines on (or about) February 1 and August 1. Each Call summarizes relevant policies and procedures, and provides important information about telescope and instrument performance. Current NRAO Call for Proposals.

The NRAO maintains a Student Observing Support Program for astronomical research by graduate and undergraduate students at U.S. universities and colleges. This program is intended to strengthen the proactive role of the Observatory in training new generations of scientists and telescope users.

Proposal Preparation

The Proposal Submission Tool used by scientists to prepare and submit their observing time requests is available via NRAO Interactive Services. Proposers should consult relevant technical documentation about the capabilities of the telescope(s) and instrument(s) requested for their proposals. The NRAO staff can be consulted via the Help Desk.

Proposal Evaluation &  Time Allocation

Beginning with the proposal submission deadline of 1 February 2011, the NRAO changed its proposal evaluation and time allocation process to an Observatory-wide panel-based system that is no longer telescope-based and that depends on community members for scientific review and NRAO staff only for technical review.

Observing Preparation

Successful proposers provide the observing details required to schedule the desired NRAO telescope(s) and acquire scientific data. These details are captured in the form of Scheduling Blocks, which are NRAO's "atomic units" of observing.


All operational NRAO telescopes employ dynamic scheduling to ensure that observing projects benefit from the best possible conditions. The NRAO staff manage the logistics of dynamic scheduling.

Data Processing

Scientists using NRAO telescopes employ a variety of software and analysis packages to reduce and analyze their data, depending on their specific needs, experience, and skills.

Publication Support

When requested, NRAO will pay 100% of the page charges for authors at U.S. scientific or educational institutions when the paper reports original observations acquired with any NRAO instrument(s), and the paper contains original analyses of archival data and/or is based on a significant amount of previously unpublished archival data. NRAO may, in some cases, support page charges for papers containing original instrumental or theoretical analyses with direct implications for existing or planned NRAO facilities.

Please visit the NRAO Library website for additional information regarding publication support by NRAO.

News Releases 

If you discover something potentially newsworthy using an NRAO telescope, our Education and Public Outreach team would welcome the opportunity to work with you to bring public recognition to your result.

Data Archives

Raw data and calibrations for all observing projects are made publicly available through the NRAO Data Archives after a proprietary period of 12 months following a project's last observation.