This page describes JWST General Observer (GO) proposals and the requirements for submitting a GO proposal.

General Observer (GO) proposals request new JWST observations and may be submitted for any amount of observing time.

General information and requirements

How GO proposals are categorized

GO proposals are categorized by their size, based on the total charged time including overheads, as Very Small, Small, Medium, or Large. GO proposals of different sizes have different requirements. In general, proposals are either accepted or rejected in their entirety. Accordingly, proposers are urged to request the actual number of hours required to achieve the proposal science goals.

GO proposals of any size can have additional "flags" to highlight particular features of those programs. These additional flags are optional (not every GO program will need one). Proposals may include multiple flags, though some specific combinations are not allowed. These flags include: 

• Calibration;
• Combined GO+AR;
• Future Cycles;
• Joint Observing;
• Pure Parallel;
• Target of Opportunity (ToO); and
• Treasury.

Each flag has additional requirements that need to be met.

Components of a GO proposal

The targets and observation specifications of a GO program are defined in APT. Proposers should consult JWST Filling Out the APT Proposal Form and JWST Astronomer's Proposal Tool Overview for information.

All GO proposals are required to include a "Scientific Justification" and "Description of Observations" in the PDF attachment.

• The "Scientific Justification" section should present a balanced discussion of background information, the program's goals, its significance to astronomy in general, and its importance to the specific sub-field of astronomy it addresses.
• The "Description of Observations" section should describe the overall experimental design of the program, justifying the selection of instruments, modes, exposure times, and requirements.

Some GO proposals may require additional sections, such as "Special Requirements," "Justify Coordinated Parallel Observations," "Justify Coordinated Observations with Other Facilities," and "Justify Duplications." Proposers should consult those links to determine whether their proposal requires any of those sections.

Additional components of a GO proposal may include:

• Laboratory astrophysics relevant to JWST observations.
• Ground-based observations that complement JWST observations. Note that these observations are generally obtained independently, as STScI does not award time on ground-based facilities except for Joint Observing programs awarded as part of this Call.
• A citizen science component in support of the program science goals. NASA document SPD-33 provides guidelines on citizen science projects.

Note: Funded support for associated ground-based observations, laboratory astrophysics, and citizen science must be compliant with the  STScI General Grant Provisions (GGP) and is limited to no more than 10% of the total budget. These components must be specified and justified in the original science proposal and may not be added subsequent to acceptance.

Special requirements

Any time-constrained observations will have additional special requirements which must be properly stated and justified in the proposal PDF attachment and/or APT proposal form. Proposers should carefully consult JWST Observations Needing Special Requirements for this information. Some examples of such observations include (but are not limited to):

• Solar System (i.e., moving) targets;
• Targets of Opportunity (ToO);
• Transit, eclipse, or occultation events (including exoplanets and brown dwarfs);
• Flares or other variability;
• Observations requiring a specific orientation on the sky;
• MIRI MRS dedicated sky background observations.

Proposers should note that all JWST observations are accepted with the understanding that the timescale on which the observations will actually be obtained will depend on scheduling opportunities and demands on JWST resources. Programs, particularly those with significant scheduling constraints, may require execution over a period that may extend into future cycles.

Certain GO proposal size categories and flags have additional special requirements that will need to be addressed, as detailed in those sections.

GO proposal size categories

A GO proposal may be submitted for any amount of observing time. GO proposals are classified as Very Small (≤20 hours), Small (>20 and ≤50 hours), Medium (>50 and ≤130 hours) and Large (>130 hours). The classification into these categories is based on total charged time, including overheads.

JWST will be offering up to 7,700 hours for observations in Cycle 6. Based on the Cycle 5 proportional allocation, we anticipate that the distribution of hours among proposal size categories will be approximately 1,000 hours for Very Small, 2,300 hours for Small, 3,000 hours for Medium, and 1,400 hours for Large and Treasury programs. The exact allocation to each size category is subject to adjustment based on proposal pressure. 

GO proposals of different sizes have different page limit requirements for the PDF attachment, exclusive access periods, are evaluated by different panels, and may have other additional requirements. Please see below for important information for each size category.

Very Small

Very Small GO proposals are those that request less than or equal to 20 hours of total charged time.

In general, Very Small GO proposals:

• have default Exclusive Access Periods of 12 months, though shorter periods are possible to request;
• have PDF attachments whose required sections are limited to four (4) pages, unless they are Combined GO+AR and/or Treasury programs. Proposers should carefully review the PDF attachment page limit requirements;
• will be reviewed by:
  • the Discussion Panels, if they are a Target of Opportunity (ToO) program;
  • the Executive Committee, if they are a Treasury and/or Pure Parallel program;
  • the External Panels, otherwise.

Further details on the review process are given in JWST How Your Proposal is Evaluated;

Very Small GO proposals with additional flags must also meet those additional requirements.

Small

Small GO proposals are those that request above 20 hours but less than or equal to 50 hours of total charged time.

In general, Small GO proposals:

• have default Exclusive Access Periods of 12 months, though shorter periods are possible to request;
• have PDF attachments whose required sections are limited to four (4) pages, unless they are Combined GO+AR and/or Treasury programs. Proposers should carefully review the PDF attachment page limit requirements.
• will be reviewed by:
  • the External Panels, for all science categories except Solar System Astronomy and Interstellar Gas and Dust;
  • the Discussion Panels, if:
    • they are to be evaluated by the Solar System Astronomy or Interstellar Gas and Dust panels; or
    • they are a Target of Opportunity (ToO) program, regardless of science category;
  • the Executive Committee, if they are Treasury and/or Pure Parallel programs.

Further details on the review process are given in JWST How Your Proposal is Evaluated.

Small GO proposals with additional flags must also meet those additional requirements.

Medium

Medium GO proposals are those that request above 50 hours but less than or equal to 130 hours of total charged time. The Medium proposal category exists to ensure that compelling science programs that demand a medium-size time request have appropriate opportunities for success. 

In general, Medium GO proposals:

• have default Exclusive Access Periods of 12 months, though shorter periods are possible to request;
• have PDF attachments whose required sections are limited to five (5) pages, unless they are Treasury programs. Proposers should carefully review the PDF attachment page limit requirements;
• will be reviewed by:
  • the Executive Committee, if they are Treasury and/or Pure Parallel programs;
  • the Discussion Panels, otherwise.

Further details on the review process are given in JWST How Your Proposal is Evaluated;

Medium GO proposals with additional flags must also meet those additional requirements.

Large

Large GO proposals are those that request more than 130 hours of total charged time. These programs should lead to a clear advance in our understanding in an important area of astronomy. They must use the unique capabilities of JWST to address scientific questions in a comprehensive approach that is not possible in smaller time allocations. Selection of a Large proposal for implementation does not rule out acceptance of Very Small, Small, or Medium proposals to do similar science, and vice versa.  But, as with all programs, target duplication and overall program balance will be considered.

In general, Large GO proposals:

• have no Exclusive Access Period. Proposals may request an exclusive access period >0 months; that request must be justified in the "Special Requirements" section of the PDF attachment and will be subject to TAC review;
• have PDF attachments whose required sections are limited to six (6) pages. Proposers should carefully review the PDF attachment page limit requirements;
• will be reviewed by the Executive Committee. Further details on the review process are given in JWST How Your Proposal is Evaluated.

Large GO proposals with additional flags must also meet those additional requirements.

Next: JWST Additional Flags for GO Proposals