Semester Observing Opportunities

Semester proposing opportunities are announced through a Call for Proposals. The observing proposal submission deadlines for Observatory facilities are the closest date to 01 February and 01 August that fall on a Wednesday1 each year. The February deadline applies to requests for observing time from 1 August–31 January; the August deadline applies to requests for time from 1 February–31 July. Proposals for the Semester Observing Opportunities must be submitted between the announcement of the Call for Proposals and the proposal deadline. The Call for Proposals contains the implementation parameters and procedures and is available online at https://science.nrao.edu/observing/call-for-proposals.

In response to a semester Call for Proposals, three proposal types can be submitted for the standard semester deadlines each year:

  • Regular proposals are for modest total time requests on Observatory facilities. The Call for Proposals specifies the maximum number of hours a Regular proposal is allowed, which may depend on the capabilities of a facility.
  • Triggered proposals are for pre-planned observations of transients whose event times are unknown a priori.
  • Large proposals are for large total time requests on Observatory facilities. The Call for Proposals specifies the maximum number of hours a Large proposal is allowed, which may depend on the capabilities of a facility.

Triggered Proposals

For a Triggered proposal that is not considered Large, users shall specify the proposal type as "Triggered" in the PST. If a proposal is partially Triggered, the entire proposal is considered a Triggered proposal. If the proposal is also Large, users should specify the proposal type as "Large" in the PST and provide clear triggering criteria in the scientific justification.

Joint Proposals

Joint proposals with non-AUI facilities and commensal observing are proposed for within the scope of these proposal types, see Section 3.2.3 and Section 7.4, respectively. Note, Large proposals can have triggering criteria; users should specify the proposal type as “Large” in the PST. When determining whether a joint proposal qualifies for as a Large Proposal, the total time requests are evaluated per facility and not as an aggregate sum. When a facility, such as the VLA or GBT, is requested as part of the VLBI/HSA or GMVA, its time is categorized under the VLBI/HSA or GMVA facility for the purpose of meeting the criteria of a Large Proposal. However, if the same facility (like VLA or GBT) is simultaneously requested as a joint resource apart from being an element of the aforementioned facilities, their respective time requests remain distinct and are not compounded when assessing against the Large Proposal threshold.

Requests for Future Capabilities

Proposals submitted to a semester call must contain capabilities offered in that semester call. An exception is for a PI who is a graduate student, who may propose up to one semester in advance for capabilities offered on the GBT, HSA, and VLBA. For the VLA, a PI who is a graduate student may propose for any array within one VLA configuration cycle (see Section 7.1 for definition). For other exceptional cases, please seek guidance from the NRAO Science Helpdesk. Submission of such cases will be subject to the NRAO's discretion.

1 The exact call period will be announced in the Call for Proposal.

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.

The National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 "to promote the progress of science; to advance the national health, prosperity, and welfare; to secure the national defense..."

AUI collaborates with the scientific community and research sponsors to plan, build, and operate cutting-edge facilities. We cultivate excellence, deliver value, enhance education, and engage the public.