Joint NRAO and GBO Telescope Time Allocation Process

Proposals to the National Radio Astronomy Observatory (NRAO) and the Green Bank Observatory (GBO) for the scientific use of its telescopes are evaluated on the basis of scientific merit and technical feasibility using a panel-based proposal review system.  This joint process is run by the NRAO in accordance with its policy of non-discrimination and inclusion.

Joint Observing Program

Observations that require combinations of the GBT, VLBA, and/or the VLA should submit a proposal for each of the requested telescopes.  The same Scientific Justification should be submitted with each proposal, and it should contain a clear justification for each telescope requested.  VLBI proposals which request the GBT or VLA as elements of the VLBI array do not need separate proposals.  For more details see the Joint Proposal page.

Access to joint observations with external facilities will continue for the VLA, VLBA and GBT for semester 24B. This includes joint observations with ALMA, the James Webb Space Telescope (JWST), the Hubble Space Telescope (HST), the Swift Gamma-Ray Burst MIssion, the Chandra X-ray Observatory, the XMM-Newton Project, NICER, and the Fermi Gamma-ray Space Telescope. For more details see the Joint Proposal page.

Director's Discretionary Time Including Education and Public Outreach

Proposals for Director's Discretionary Time (DDT) may be submitted at any time. They must be submitted through the PST. DDT proposals are intended to address targets of opportunity, high-risk/high-return exploratory time, or other science opportunities deemed sufficiently urgent to justify prompt action. 

DDT proposals may also be submitted for the purpose of education and public outreach---for example, to image an iconic source or to support an educational opportunity for students. Such proposals should clearly justify the requirements for the requested time allocation and observing mode on any given instrument, and should describe the anticipated impact of the observation.  

While there is not an a priori limit to time that can be requested via DDT, it is expected that no more than 5% of the available science time on each telescope will be allocated for this purpose.

Other Proposal Opportunities

The NRAO would like to make users aware that there are additional proposal opportunities as follows:

• High Risk Proposals: As a means of maximizing its scientific impact through cutting-edge observations, the Observatory encourages the submission of high-risk/high-reward proposals.
• Commensal Observing: Commensal observations can be an effective way to maximize observing hours on NRAO telescopes, by allowing multiple experiments or systems to run simultaneously, when resources allow.  The Observatory may support two kinds of commensal observing:  commensal observing projects, and commensal systems.  For more information see the Commensal Observing with NRAO Telescopes page.
• Filler Programs: Some programs are not time critical, not strongly dependent on array configuration, or do not require highly subscribed LST ranges. Such programs may be able to take advantage of "filler" time.   The proposal should make clear in the abstract and early in the science justification that "filler" time is being requested.  If “filler” time is requested, the proposal will be ineligible for scheduling priority A or B.
  

Further information about each of these programs can be found on the Proposal Opportunities page.