Observation Scheduling, Project Completion, and Carry-over

Science observations will be scheduled taking into account many factors, including, for example, the weather and proposal grade. The individual SBs of approved projects will remain in the observing queue until one of the following two criteria are met:

  1. The allocated time of a project has been executed.
  2. The potential scheduling period has ended.

For semester proposals, Section 4.3 defines the relevant scheduling periods for Regular, Triggered, and Large proposals. VLA DDT proposals remain in the observing queue for the configuration they request or until the end of the observing semester, whichever occurs first. VLBA and GBT DDT proposals remain in the observing queue until the end of the observing semester. If a project is not completed within these time frames, the project is considered terminated and the proposers should consider submitting a new proposal in the appropriate Call for Proposals.

For both semester and DDT proposals that are dynamically scheduled observations, if the dynamic constraints are no longer satisfied, they may be returned to the scheduling queue, provided the project is in the General Observing category. Re-observation is not guaranteed in such a case.  If observers believe that an observation should be failed after inspecting their data they should submit a ticket to the NRAO Science Helpdesk as soon as possible and in all cases prior to the expiry of the period of eligibility for scheduling. Please contact the NRAO Science Helpdesk for clarification concerning specific projects.

Generally, approved Large proposals are accepted in their entirety for the duration of the program; that is, the Observatory will commit the resources required to discharge the proposal within the constraints imposed by scheduling guidelines even though it may take multiple semesters to do so. The Observatory requires annual progress reports from all Large proposals and reserves the right to revisit allocations made to a given Large proposal if insufficient progress is demonstrated. Specifically, the following aspects of the proposal are considered:

  • A project connected to a Large proposal is required to maintain and provide timely updates to their online resources, otherwise their project may be terminated or future proposals rejected. An approved Large proposal must provide a web link for the Large proposals page7 before observations are scheduled. Initially, this can be a simple web page that describes the project but this page is expected to be kept up to date.

  • A project connected to a Large proposal is required allocate sufficient resources (e.g., observers) for successfully completing the project, otherwise their project may be terminated or future proposals rejected.

As much as 25% to 50% of available Open Skies observing time on Observatory telescopes is allocated to Large proposals. The final percentage will depend on proposal pressure and scientific merit, as determined by peer review. Large proposals will be further constrained to a maximum of 50% of the available Open Skies observing time in any LST range during any semester (or array configuration for the VLA).

The Observatory allocates telescope time and therefore does not guarantee that a specified sensitivity will be obtained. For qualifying programs, the data are run through the Science Ready Data Product (SRDP) pipeline and the proposers are notified of the available pipeline datasets; see the resources online https://science.nrao.edu/srdp/home for more information.

Further details pertaining to scheduling are available online: 

GBT https://science.nrao.edu/facilities/gbt/schedules/dynamic
VLA https://science.nrao.edu/facilities/vla/docs/manuals/obsguide and in memorandum “A Brief Description of the VLA Prioritizer”
VLBA https://science.nrao.edu/facilities/vlba/observing/dynamicguide

7 For VLA and VLBA Large proposals, see https://science.nrao.edu/science/science-program/large-proposals. For GBT Large proposals, see https://greenbankobservatory.org/science/gbt-surveys/.

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.