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. 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.

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.

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