Unauthenticated users (unregistered users, or users who are registered but have not logged in) have access to non-proprietary data from Observatory facilities, documentation, tools (e.g., sensitivity calculator, Archive Access Tool), and the NRAO Science Helpdesk Knowledgebase articles describing solutions to common questions and problems.

Authenticated users, i.e., those who register for a NRAO account and are logged in, may participate in Observatory proposals, access their proprietary data through the Archive Access Tool, track the progress of their projects, and submit tickets to the NRAO Science Helpdesk.

Anyone can register for a NRAO account through the online portal. A user may have one (1) NRAO account, which is identified by a unique, user-selected username. Users are required to provide their first and last names, their affiliation, a street address, an email address, and a phone number. The fields requesting demographic information, such as career stage, gender, and graduation year, are voluntary. User information follows the Observatory’s Confidentiality of Information Policy in Section 2.2. If a duplicate user profile exists or is mistakenly created, please contact the NRAO Science Helpdesk for assistance.

Users are responsible for ensuring that their profile information is correct and up-to-date. The Observatory strongly encourages users to check the spam folder of their email in case official communication is mistakenly directed there.

All registered users agree to act according to Observatory policies and procedures, as defined in this document and in the Call for Proposals documentation. In particular, all users accept the limitations of the observing capabilities and operational restrictions applicable for the call for which they submit a proposal. Any registered user may submit a proposal for the supported facilities.

Each proposal must identify an individual who will serve as Principal Investigator (PI). Proposals submitted by a consortium are not valid. Instead, a person within the consortium should submit the proposal and act as PI and any other consortium members are co-Investigators (co-Is). The PI or a co-I is required to be specified as the official contact between the Observatory and the proposing team for all proposal correspondence. By default, the PI is the official contact. The PI and all co-Is are responsible for ensuring that their respective profiles registered for the NRAO user account are correct (e.g., email address, affiliation). Proposals may include any number of co-Is.

By submitting a proposal, the PI takes full responsibility of its contents. The PI is responsible to ensure that all co-Is have agreed to be included on a proposal. Including a user as co-I in a proposal without their consent may lead to the proposal being canceled. Co-I names cannot be added to or be withdrawn from the proposal after the proposal deadline.

PIs and co-Is may all view, edit and submit proposals in the PST. Additionally, they all may create, modify, and submit Scheduling Blocks in the relevant workflow (e.g., Observation Preparation Tool; OPT). They are all entitled to receive help from, or discuss project details with, Observatory staff and receive the outcome of the review process.

Proposals are evaluated on the basis of scientific merit. Proposals may also be reviewed for their feasibility by Observatory staff. A feasibility review may include a technical review, a data management review, or both. Unless otherwise noted in the Call for Proposals, semester proposals utilize the Panel Proposal Review process and DDT proposals utilize the Observatory Site Review process. The review process for special calls will be provided in the notice for the special call. Details about the Panel Proposal Review process are available online at https://science.nrao.edu/observing/proposal-types/proposal-review-system. The Observatory Site Review process is a less formal review process whereby primarily Observatory staff will provide information for the scientific, technical, and/or data management components of the proposal review.

For the Panel Proposal Review Process, the Observatory is responsible for recruiting reviewers for the Science Review Panels (SRPs) and TAC. The Observatory is committed to the principles of equity and inclusion in the peer review process. As such, it is a goal of recruiting that the demographics of the review panels and TAC reflect the gender demographics of the astronomical community⁴.

The Observatory welcomes volunteers to be a science reviewer for the Panel Proposal Review process. To apply to volunteer, please submit the online form at https://science.nrao.edu/observing/proposal-types/srp-volunteer-form. For more information about the volunteering and the review process, see online at https://science.nrao.edu/observing/proposal-types/volunteer_review.

Membership of the SRPs is kept confidential by the Observatory, but SRP members are welcome to note their participation (in their curriculum vitae, for example). Membership of the TAC is made public by the Observatory. For the most current semester, the TAC membership is available online https://science.nrao.edu/observing/proposal-types/time-allocation-committee.

⁴ The specific recruitment goals are determined by the demographics of the Observatory’s user base, which relies on users to provide their information. Gender-related reports are available at https://science.nrao.edu/science/reports/gender-related-systematics-in-the-nrao-and-alma-proposal-review-process

The purpose of the proposal-selection process for Observatory telescopes is to select the proposals that potentially are most valuable for the advancement of scientific knowledge. This does not necessarily mean giving high marks to those proposals that will provide sure results; it also includes a careful consideration of well-reasoned proposals that may be unconventional, but provide opportunities for new discoveries. In the evaluation of proposals, reviewers consider how best to exploit the full capability of the unique scientific instruments that the Observatory operates for the community. Reviewers may also consider other factors such as

Publication record

Due recognition should be given to teams who have an established publication record for past related proposals. In contrast, some observers may have considerable data that clearly has not been analyzed and published yet.

Possibility of acquiring more appropriate data

Reviewers may also wish to consider the possibility that other data may be more appropriate for reaching the scientific goals of the proposal. For instance, the relevant data might already exist in the Archive (available through the Archive Access Tool).

Selection of resources

Reviewers may judge whether the requested observations are an appropriate approach to meeting the stated science objectives.

Resource requirements

Reviewers may take into account the amount of resources requested. For example, a particular proposal or scientific goal may be viewed as a valuable use of 4 hours of telescope time, but may not be as valuable if it requires 80 hours of time.

Student status

The Observatory encourages the use of its facilities for student research, particularly for PhD dissertations. In this case, it is most helpful if the proposal will say in some manner how the proposed observations will be used in the dissertation, and whether they are a sidelight or a main focus of the thesis. Reviewers are encouraged to comment on this topic and may choose to support proposals more strongly if there appears to be a well-thought-out program of student research.

A Disposition Letter is sent to the PI and co-Is for semester and DDT proposals. Disposition Letters are also available in the PST for proposers to review. For the semester proposals, this letter contains comments from the cognizant SRP, a linear-rank score from the SRP, comments from the feasibility review (if available), comments from the TAC (if available), and the scheduling priorities. For DDT proposals, this letter contains a brief notice of approval or justification if declined.

A scheduling priority is assigned to each session of a proposal, which is guided by the outcome of the SRPs (e.g., linear-rank score) or the Observatory Site Review, and takes into account the time available on a facility. It is the policy of the Observatory to not allocate all of the available observing time in any LST/GST range during any semester to a single proposal; this includes Joint Proposals. There are five different scheduling priorities:

The scheduling terms described above apply unless explicitly stated otherwise in a Disposition Letter. Disposition Letters may include a Scheduling Priority marked with an asterisks (^∗; e.g., N^∗); this is used to indicate that there are specific comments from the SRP, TAC, or Observatory Staff to the proposing team regarding the requested resources. Proposers should review the comments that are returned in the Disposition Letter before proceeding to observation preparation (Section 5.1). In the event that clarification is needed about technical comments, please submit a ticket to the NRAO Science Helpdesk and select the “VLA/GBT/VLBA Proposal Review” topic.

The outcome of the proposal review process is final. If an unfavorable disposition is received, the Observatory strongly encourages authors to prepare a new proposal for a future semester that addresses the returned comments. It is the policy of the Observatory to not allow communication between science reviewers and authors, even mediated through a third party such as the Observatory staff.

In case of questions about details in the Disposition Letter, please submit a ticket to request clarification through the NRAO Science Helpdesk and select the “VLA/GBT/VLBA Proposal Review” topic. However, in no case will such a request lead to a revision of the linear-rank or scheduling priority assigned to the proposal as a result of the review process.

 ⁵ See the definition of a VLA configuration cycle in Section 7.1

With the increasingly flexible capabilities being offered on Observatory facilities, there may more frequently be partial conflicts between proposals in terms of source(s), spectral line(s), array configuration (VLA), observing band, correlator/spectrometer set-up, and science goals. For proposals submitted on the semester submission deadlines, proposal conflicts are handled by the normal proposal evaluation and time allocation process. Proposals for DDT, however, may be submitted at any time and may conflict with a proposal that has already been approved through the standard time allocation process, or has previously been observed with the data still proprietary. Under these circumstances, for the overlapping science goals,

• Any proposal that has been previously approved through the normal time allocation process with priority A or B, but has not yet been observed, will take precedence over the DDT proposal.

• Proprietary data that have already been observed, including that for priority C and D projects, at the time of the DDT proposal submission will also take precedence over the DDT proposal.

The DDT proposal will be evaluated only on the part of its science goals that cannot be derived from the observations associated with the previously-approved proposal or previously observed proprietary data conflicted with the DDT proposal. If a DDT proposal is approved on these grounds, the DDT team may be given the option of either:

• employing an observing set-up that does not conflict with the previously-approved or previously-observed proposals, or

• to use the previously-approved proposal’s proposed set-up; in this case the conflicting/overlapping data will be made immediately available to the proposers of the previously-approved proposal.

The definition of the conflicting/overlapping data is defined in Appendix A.3, and the Observatory utilizes the source list and resources provided in the proposal to determine potential conflicts.

There may be cases where more than one DDT or ToO programs are triggered on the same object nearly simultaneously. Should such a situation arise, the NRAO Director or designee will take the final decision on which program will be observed. Typically, it will be based on the order of proposal submission, with priority given to the first received proposal. Other factors may be considered, including the requested observing frequency and the prevalent weather conditions.

If a proposal’s Disposition Letter indicates that time is allocated at a scheduling priority of A, B, C, or D then Observatory staff will convert the proposal to a project which is eligible to compete for time in the dynamic queue. All observations on Observatory facilities are executed using the concept of Scheduling Blocks (SBs), although the blocks may not be specifically called Scheduling Blocks. An accepted proposal might require tens or hundreds of Scheduling Blocks to gather the data necessary for exploring that project’s objectives.

It is the responsibility of the proposing team to prepare for observations. Proposers should review the technical and science comments that result from the review process when preparing their project for observation. Failing to create Scheduling Blocks will result in the awarded time to be forfeited. At any point in the project preparation process, a project may be withdrawn, and a NRAO Science Helpdesk ticket should be submitted in such an event.

Each facility may have unique requirements for preparing a project for observation. It is the responsibility of the proposing team to familiarize themselves with the requirements and resources that are relevant to their project. Users should submit a ticket to the NRAO Science Helpdesk if they have questions. The links below to should also be reviewed by users.

VLA, VLBA, and GBT observing are classified into two categories: General Observing (GO) and Shared Risk Observing (SRO). The GO category includes the standard capabilities of VLA, VLBA, or GBT whereas the SRO program accommodates those who seek to utilize the facilities beyond their regular capacities. The Call for Proposals provides a detailed outline of what constitutes these categories for each facility.

The Observatory expects that most SRO programs will have no or only minor problems that can be corrected quickly. If an SRO program fails, however, and it becomes clear that detailed testing with additional expertise is needed, then the project must make an experienced member from their team available to help troubleshoot the problem. In some cases, this may require the presence of that experienced member. If adequate support from the project is not given, then the time on the telescope still will be forfeited. The additional effort is to be determined based on discussions with the Observatory staff and management and the project team.

VLA or VLBA SRO proposals will not be carried over if they cannot be scheduled for reasons associated with the shared risk component(s) of the observations, even if awarded priority A. VLA or VLBA RSRO proposals will not be awarded priority A, but would be subject to the same conditions on carry-over as SRO proposals. Those projects in the VLA or VLBA Shared Risk and Resident Shared Risk categories may not be re-observed if they fail due to problems with the shared risk/resident shared risk component(s) of the observation. 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.

For GBT SRO, the proposing team may be asked to provide a "backup" receiver if the original one is not available. In such cases, the observation may proceed with the backup receiver, as long as the observation is not considered a duplicate observation, as defined in Section 7.3.

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: 

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/.

Any situation that is unforeseen or for which ambiguity exists in this Users’ Policies document or in the associated Call for Proposals material will be referred to Assistant Director for Science Support and Research, whose decision is final.

The Observatory reserves the right to change the policies defined in this document at any time. Barring unforeseen emergencies, such changes will apply at the start of the observing semester following the date of their introduction. These changes will be published in the Users’ Policies document at the Call for Proposals and the proposers should review the policies with each proposing cycle.

This Users’ Policies document attempts to maintain consistency with the ALMA Users’ Policies Document when applicable; however, it is independent from the ALMA version and should be treated so.

The majority of these policies and guidelines are taken from the existing online documentation available at https://science.nrao.edu, which has been maintained diligently by Observatory staff over the years. As noted earlier, this information and policies in this document supersede the online content and other documents if conflicts exist.

The “Plan of Dissertation Research” should be submitted with their first proposal. This plan can be referred to in later proposals; instructions for how to upload or replace a plan are available here.

The Plan of Dissertation is important in the proposal review process and should be well written; it is not a placeholder and should not be a replica of the proposal. The plan must be compliant with the follow requirements:

• It must follow the Observatory's Plan of Dissertation Research template. The template is available below in word or latex formats:
• word template,
• latex template.
• The section headers in the template should not be changed but the instructional text within the template should be replaced.
• It must be uploaded as a Portable Document Format (pdf).
• It is a maximum of two (2) pages.
• There is a minimum of one inch margins on all sides and the pages are US letter size.
• The minimum font size is 11 point, which includes the font in figure captions, table captions, table headers, content, and references. Fonts in rescaled figures should be legible.
• All sections of the plan must be authored by the student.

The plan provides some assurance against a dissertation being impaired by adverse referee comments on one proposal, when the referees do not see the full scope of the project. Students should keep their expected graduation date in the user profile (Section 2.1) and in the thesis time line updated, as the date of data acquisition must fall within the timeline of the PhD. If the observing semester occurs after the student intends to graduate, then it is not appropriate to indicate that the proposal is for a dissertation. While not a guarantee, the Observatory allows reviewers to consider elevating the proposal in the rankings if it is associated with an acceptable Plan of Dissertation. This is given in consideration to the time constraints students typically operate under, as having to resubmit a proposal due to minor criticisms may not be possible within the scope of their studies. Therefore, it is advantageous for students to provide a thoughtful and thorough Plan of Dissertation if their PhD research is reliant on the proposal data.

Note, the PST does not validate Plans of Dissertations.

A proposed observation is considered a duplicate of another observation if all of the following conditions are met:

• Target field location
• For a single-field, the proposed position coincides within the half-power beam width of the
  other observation. Moving objects (e.g., Solar System objects) will be identified by name.
• For mosaic observations, more than 50% of the proposed pointings are within the half-power beam width area covered by the other observation.
• For evolving or variables sources, the duplication is not scientifically justified.
• For GBT monitoring programs, no two active programs can monitor the same proposed position that coincides within the half-power beam width of the other observation. Moving objects (e.g., Solar System objects) will be identified by name.
• Angular Resolution
• The proposed angular resolution differs by a factor of ≤ 2 from the other observation.
• Spectral Windows
• For the VLA and VLBA,
• Continuum: The requested sensitivity (rms) for the aggregate bandwidth is better by a factor of ≤ 2 from the other observation and the requested frequency is within a factor of 1.3.
• Spectral line: If the central frequency in any requested correlator window is encompassed by the other observation and the sensitivity per spectral channel, after smoothing to the same spectral resolution, is better by a factor of ≤ 2. Or, if the spectral resolution, as justified by the science case, is better by a factor of ≤ 2.
• For the GBT,
• Continuum: The requested sensitivity (rms) for the aggregate bandwidth is better by a factor of ≤ 2 from the other observation and the requested frequency is within a factor of 1.3.
• Spectral Lines: Within the largest beam size of two receivers with overlapping frequency ranges, any spectral line being the same while taking into account velocity/redshift.

Solar observations will not be checked for duplication.

Commensal observations can be an effective way to maximize observing hours on Observatory 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.

Commensal observing projects refer to peer-reviewed, PI science projects which can be done simultaneously on Observatory telescopes using Observatory backends to conduct two different experiments concurrently. Investigators wishing to carry out commensal observing projects submit independent science proposals as separate primary and secondary proposals, which go through the normal time allocation processes, and are subject to standard data policies.

Commensal systems may be backends or data pipelines which have been approved to run on Observatory telescopes while some PI science experiments are running. Commensal observing systems which are currently on the VLA are described at the proposing page.

A primary proposal controls the telescope pointings and requests the full amount of telescope hours required to fulfill the science objectives detailed in the proposal. Secondary proposals are to run commensally with the primary pointings but make no formal request for an allocation of telescope time. However, when preparing a secondary commensal proposal, please ensure that a nominal amount of time is requested for a session (e.g., 0.1 hrs), even if it is a dummy session. Each proposal must contain estimates of the full resources needed (correlator setup, data rates, etc.) to carry out their specific part of the project.

During the proposal review and time allocation process it will be determined if the combination of the observing set-up and the positions by the primary or secondary proposals conflict with any approved projects. In the case of a conflict, some data restrictions may be applied to the primary and/or the secondary commensal proposal. If the primary and secondary proposals use the same back-end resources (e.g., VLA-WIDAR) it may be necessary for technical reasons to require that the investigators on both primary and commensal projects be given full access to all data.

The Observatory wishes to ensure that peer-reviewed, open-skies PI science projects which are approved via review processes are protected, and that ownership of data is defined. The concept of a “PI science project” includes the science goals and the data produced from PI-specified observing setups. The operation of all commensal systems on Observatory telescopes is subject to the below policy:

Peer-reviewed, open-skies PI science, and the associated output from standard observatory backends, take priority over commensal observing systems. Commensal observing systems may run at all times during open-skies PI science, except when they conflict directly with such science, or cannot run because of technical incompatibility. Conflict is defined by a commensal system reproducing, or being able to reproduce, any part of the PI data approved by the Observatory’s Telescope Time Allocation Committee. The Observatory requires that all commensal systems provide sufficient technical information so that determinations can be made as to whether they will conflict with PI science. The primary project science PI may choose to allow a conflicting commensal system to run; in this eventuality, the commensal system may run alongside the PI science project, subject to technical compatibility. The data produced by a commensal system are controlled by the associated commensal project team.

Observatory telescopes and backends are sufficiently flexible in many cases to allow two experiments to run commensally. To the degree that this enhances science return from the telescopes, Observatory wishes to support commensal projects subject to resource and scheduling constraints. The operation of commensal systems during other (non-open-skies) observing time is subject to the details of relevant contracts or agreements. Groups wishing to carry out commensal observations should submit independent science cases as separate primary and secondary proposals.