Constraints on Opportunities

With the global radio-astronomy community continuing to grow and new observatories adopting a variety of access models, the NRAO remains committed to an open-skies philosophy driven by scientific merit. To uphold this principle in a landscape where reciprocal, unrestricted access is not universally ensured, we are adapting our long-standing framework to preserve both the quality and equity of scientific output from our facilities.

Effective with the 26A semester Call for Proposals and Director’s Discretionary Time (DDT), the NRAO will employ institution-based country caps on the VLA1 to moderate the share of observing time allocated to non-US based institutions. Starting with the 27A semester Call for Proposals and DDT, requests for GBT resources are subject to institution-based country caps.  As Mexico is a ngVLA Development partner, individual country and total allocated time caps do not apply to proposals with PIs at institutes in Mexico.

Proposals subject to the institution-based country caps will not be allocated filler time (priority C and D).  For the semester calls, the aggregate share awarded to PIs from non-US institutions will not exceed 30% of the total allocated time, with no single foreign country receiving more than 10%. These constraints will continue for DDT proposals, except that the total limit of 30% will not apply. These constraints apply to the institutional affiliation of the PI, irrespective of personal citizenship.

1 The VLBA may be added in future semesters.

Connect with NRAO

The NSF National Radio Astronomy Observatory and NSF Green Bank Observatory are facilities of the U.S. National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

Founded in 1956, the NSF NRAO provides state-of-the-art radio telescope facilities for use by the international scientific community. NSF NRAO telescopes are open to all astronomers regardless of institutional or national affiliation. Observing time on NSF 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. NSF NRAO also provides both formal and informal programs in education and public outreach for teachers, students, the general public, and the media.

The U.S. National Science Foundation (U.S. 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.