JWST New and Important Features
Important new features for proposers to consider in Cycle 4 are covered in this article.
On this page
Investigators are reminded that those who are facing extenuating and unforeseen circumstances beyond their control that will impact their ability to meet the stated deadline have the option of contacting the JWST Help Desk to request a moderate extension. Extensions should be requested before the deadline.
What's new for Cycle 4
Observing Time in Cycle 4
- JWST will be offering 8,500 hours for observations in Cycle 4 as compared with 5,500 hours in Cycle 3. The increased allocation reflects the reduction in the tail of observations from Cycle 1. Based on the Cycle 3 proportional allocation, we anticipate that the distribution of hours among proposal size categories will be approximately 1,950 hours for Very Small, 2,900 hours for Small, 2,250 hours for Medium and 1,400 hours for Large and Treasury programs. The exact allocations will depend upon the Cycle 4 proposal pressure.
Policy
Page limits have been reduced substantially (in most cases halved). The Observing Description in APT will not be visible for TAC reviewers. Proposers should not use that free text field as a replacement for page limit space.
Following the recommendations of the JWST Users Committee (JSTUC), page limits have been reduced substantially. The bulk of the PDF file should comprise the Scientific Justification and the Technical Description (for GO programs) or Analysis Plan (for AR programs). The templates have been updated for Cycle 4 and can be found at JWST Preparation of the PDF Attachment.
- Four (4) pages are allocated for those sections in most programs (Very Small GO, Small GO, Future Cycles GO, Calibration GO and AR, Survey, Regular AR, Cloud Computing AR, Theory AR and Data Science Software AR);
- Five (5) pages are allocated for Medium GO and Combined GO+AR programs;
- Six (6) pages are allocated for Large GO, Treasury GO and Legacy AR proposals.
One additional page is available in all the above cases for the following sections: Special Requirements, Justify Coordinated Parallel Observations, Justify Duplications and Justify Coordinated Observations with Other Facilities. For Joint proposals, users should determine whether their proposal is Very Small, Small, Medium or Large based on the JWST hours request, and use the appropriate page limits. Cycle 4 DD proposals submitted after Cycle 4 starts (July 1, 2025) are also required to follow these guidelines. Cycle 3 DD proposals submitted between July 1, 2024 and June 30, 2025 should follow Cycle 3 guidelines for proposal preparation (including Cycle 3 page limits).
In relation to these page limits, note the following:
- Proposals that exceed the page limits will be subject to disqualification.
- There are no limits on the numbers of figures and tables in the PDF attachment, and they may be interspersed in the text. However, the total page limit must be observed.
- References should be listed at the end of the proposal and do not count against the page limits. References have no particular formatting requirements (you can use your favorite style, including numbering the references).
- Your PDF attachment must be prepared with a font size of 12 pt, including figure captions and references. Do not change the format of any of the templates provided by STScI. Proposals that change the font size and/or the margins will be disqualified.
- Proposers are recommended to devote at least one page to the Technical Description or Analysis Plan.
- The Observing Description in APT will not be visible for TAC reviewers. Proposers should not use that free text field as a replacement for page limit space.
- A summary of the page limits is provided in the following table:
WARNING! PAGE LIMITS
PAGE LIMITS HAVE BEEN REDUCED SUBSTANTIALLY (IN MOST CASES HALVED). See JWST Proposal Categories.
Proposal Category† | Total Page Limit for PDF Attachment |
---|---|
Very Small GO Small GO Future Cycles GO Calibration GO and AR Survey Regular AR Cloud Computing AR Theory AR Data Science Software AR | 4+1* |
Medium GO Combined GO-Archival | 5+1* |
Large GO Treasury GO Legacy AR | 6+1* |
† For Joint JWST programs, users should determine proposal size based on the JWST hours request. Cycle 4 DD proposals submitted after Cycle 4 starts July 1, 2025 are also required to follow these guidelines. Cycle 3 DD proposals submitted between July 1, 2024 and June 30, 2025 should follow Cycle 3 guidelines for proposal preparation (including Cycle 3 page limits).
* The additional page (+1) is available only for the following sections: Special Requirements, Justify Coordinated Parallel Observations, Justify Duplications and Justify Coordinated Observations with Other Facilities (i.e. descriptions of Joint programs).
- Science Categories
The Science Categories have been adjusted to better match JWST science topic distributions, based on previous JWST cycles. The categories are:
Galactic: Solar System; Exoplanet Atmospheres and Habitability; Exoplanetary System Formation and Dynamics; Stars and Stellar Populations; Gas, Dust and the ISM;
Extragalactic: Nearby Galaxies to Cosmic Noon; High-Redshift Galaxies and the Distant Universe; and Super-Massive Black Holes and Active Galaxies.
For more details see the description in JWST Proposal Selection Procedures.
- Exclusive Access Period (EAP)
The current default EAP for most programs is 12 months; discussions are currently on-going regarding a possible reduced, non-zero value. At this time, no decisions have been taken. The feedback from the community survey is an important factor in the outcome.
The MIRI observations of coronagraphic PSF reference star-associated background targets has now zero exclusive access period, thus matching their corresponding PSF reference stars observations.
- Aperture Position Angle (orientation) constraints
If your program requires observations at specific orientations, list that information in the Special Requirements section of the PDF attachment. The requirements must also be listed in the Special Requirements section of APT. Failure to do so may lead to those requests not being met.
- APT template
As in Cycle 3, Proposers should make sure that they the mark the APT coversheets appropriately using the menus that expand out on the Proposal Information page. If these fields are not marked and filled out in the APT coversheet those requests may not be met, even if they are described in the proposal. Key fields are highlighted in the Figure below. For more information, see Filling Out the APT Proposal Form.
APT screenshot that highlights some of the special fields that will need to be filled out as applicable. - Use of Generative Artificial Intelligence (GAI) technology
NASA currently does not have a policy on the use of Generative Artificial Intelligence (GAI) technology to support proposal writing and review. In the interim, STScI is adopting the approach recommended by the National Science Foundation.
- Reviewers are forbidden from uploading proposal content or review materials to GAI tools since this violates the confidentiality of the review process.
- Proposers are discouraged from using GAI in constructing proposals. If they do use such tools, they must describe how they were used as part of the proposal submission. This statement should be included in the Team Expertise section.
Proposers are reminded that using Generative AI tools will place that text in the public domain.
- Multiple in-cycle submissions
Before the proposals are distributed to the reviewers, STScI checks all submitted proposals for multiple in-cycle submissions across scientific categories and across size categories. By multiple in-cycle submissions we refer to proposals with the same or nearly the same team, science goals, and targets. STScI reserves the right to reject all such proposals as non-compliant in the case of egregious violations, as they negatively impact the fairness of the selection process and result in unnecessary burden for the reviewers.
Proposal Review
- Proposal Size Boundaries have changed. As recommended by the JWST Users Committee (JSTUC), GO proposal size boundaries have changed to achieve a more balanced workload and responsibility in time allocation for the External and Discussion panelists and the Executive Committee (EC), and to accommodate the growing complexity of JWST programs. GO Proposals are now classified as Very Small (≤ 20 hours), Small (> 20 and ≤ 50 hours), Medium (> 50 and ≤ 130 hours) and Large (>130 hours). The classification is based on the total charged time, including overheads. Very Small GO proposals and Regular AR proposals will be reviewed by the External panels. Small and Medium GO proposals and all Target of Opportunity and Survey proposals, regardless of size, will be reviewed by the Discussion panels. The EC will review Large GO proposals, Treasury GO programs, Legacy AR programs and other requests for substantial resources, such as large Pure Parallel programs. Further details on the review process are given in JWST Proposal Selection Procedures.
- The Executive Committee has been split in two (Galactic and Extragalactic). Based on recommendations by the Cycle 3 EC to reduce workload and to better match reviewers' expertise, the Cycle 4 Executive Committee review will be split into two parts: Galactic EC and Extragalactic EC. Discussion panels will have Vice Chairs that do not review Discussion proposals. Instead, they participate as panelists in the EC and they help the Panel Chair with Panel Chair duties. Vice Chairs will help alleviate proposal conflicts for the Panel Chair. STScI anticipates that there will be ~18 discussion panels covering all areas of astronomy and astrophysics. Discussion panels will meet virtually (the week of February 3, 2025). The Executive Committees will meet in person at STScI the following week (the week of February 10, 2025). The Galactic EC will meet Monday and Tuesday. The Extragalactic EC will meet Wednesday and Thursday. Further details on the review process are given in JWST Proposal Selection Procedures.
- Re-use of published text and dual anonymous review: Proposals may not include substantial verbatim extracts from previously published materials, including white papers or accepted proposals. Such inclusions are contrary to dual anonymous review since the re-use implicitly identifies the authors of the proposal. Proposals violating this requirement are subject to disqualification. Further details are given in the Compliance sub-section of the JWST Anonymous Proposal Review guidance.
APT
- Cycle 4 proposers should use the Astronomer's Proposal Tool (APT) version 2024.5 or higher for proposal preparation, released on August 22, 2024. Details can be found in the release notes (for current and past versions).
- Moving targets: You will now be able to visualize the track of a moving target in Aladin over short periods of time against a sky image.
- Proper motions: There is now a checkbox to indicate that proper motion is NEGLIGIBLE OR NOT APPLICABLE. Observations that require very accurate coordinates will generate an error on their target if proper motion is not supplied or the check box checked.
- Improvements to the Fixed Target Resolver: In order to clarify the details of fixed target specifications retrieved from external catalogs (such as SIMBAD) more columns have been added to the search results table including Reference System. In addition, when you retrieve SIMBAD coordinates from within APT the parallax will be retrieved and populated at the same time.
- APT only accepts fixed target coordinates specified in ICRS. This is now more clearly emphasized by the prompt in the Fixed Target form.
- MSA Planning Tool: The MPT now allows a user to specify wavelengths of interest for each of their MSA sources for MOS spectroscopy. Up to 5 wavelength ranges of interest can be specified.
- Coronagraphy: Some science cases require Target Acquisition (TA) on a star that is not the science target. You can now select two distinct targets on the MIRI Coronagraphy template: one for the TA and one for the science. The slew from the TA target to the science target is automatic. The requirement that science and PSF reference observations be linked with a Sequence Non-Interruptible requirement has been relaxed for NIRCam and MIRI coronagraphic observations to only Non-Int. Users are no longer required to specify the order of their observations, unless they choose to. Observations will still execute contiguously.
- When you display Orient Ranges in Aladin you will now see the "V3PA" displayed for the exposure's aperture. This is the position angle of the V3 axis of the JWST field of view measured east from north.
- ToO activations: There are new fields on the Proposal Information form to record the number of ToO activations of each type.
- Aperture Position Angles: Programs that require specific orientations must provide that information in the APT Special Requirements section and provide a justification in the Special Requirements section of the PDF file.
- Multi-Observatory: For GO and DD proposals that plan to coordinate observations at multiple observatories, there is a new flag on the same line as the proposal Category. When JWST is primary, you are prompted to request time on one or more coordinating telescopes. Proposers updating Multi-Observatory proposals from Cycle 3 for resubmission in Cycle 4 should read this Knowledge Article to get started.
- The warning on Time Series Observations (TSO) in a sequence non-interruptible set which exceeds 24 hours has been suppressed and replaced with an error if a TSO seq non-int set exceeds 100 hours.
Observing Description: The Observing Description entered in APT is not visible to TAC reviewers. This section is designed to provide STScI staff with information on the proposed observations.
- Target Acquisitions: APT version 2024.5 introduces some changes for TAs. For NIRCam, TAs are executed using dithered images, which is robust against new hot pixels. For MIRI LRS, TAs are optional in the slitless mode.
- NIRISS AMI Template: in APT version 2024.5 you can select the option for a Direct Image in the AMI Template on a per filter basis. So if you need Direct Images for some filters but not all, you can save time.
ETC
- Cycle 4 proposers should use the JWST Exposure Time Calculator (ETC) version 4.0, released July 29, 2024. Updates for version 4.0 include the addition of square apertures for imaging modes, updates to the handling of NIRSpec reference files, support for single-group ramps, the addition of aperture visualizations in images, a new NIRCam short-wavelength GRISM time series mode, updates to the thermal background and MIRI throughputs, and other bug fixes and usability improvements. See the release notes for details, and be sure to review the known issues for this release. Instructions for downloading the latest version of the ETC's Pandeia engine as a Python module, with the associated data, are found in the Installing Pandeia page and the Pandeia Engine News page.
- Reduced count rate in MIRI Imaging, Coronagraphic Imaging, and Medium-Resolution Spectroscopy (MRS). For MIRI Imaging, Coronagraphic Imaging and MRS calculations in the ETC, the reported signal-to-noise ratio (SNR) takes account of the reduced count rates, based on the currently observed trend projected to the end of Cycle 4 (end of June 2026). For the MRS this is an incremental update from ETC v3; for the Imaging and Coronagraphic Imaging modes this is the first implementation of the time-dependent sensitivity correction. The model used for this update matches that used for the photometric calibration of MIRI data in the JWST calibration pipeline. Further details of the count rate loss can be found in JDox for the MRS and Imager. As the loss is not observed at wavelengths covered by LRS, ETC calculations for the LRS mode remain unchanged.
Instruments
- NIRCam is now offering Grism Time Series observations using grisms in both the short and long wavelength channels, allowing spectral coverage from 0.6–5.0 µm depending on the blocking filters used. For more details, see the NIRCam Short Wavelength Grism Time Series JDox article. Observers who wish to use this new capability should also review the related observing strategies JDox page for special instructions on how to assess the Dispersed Hartmann Sensor (DHS) bright limits, and use the newly defined readout patterns to manage the data excess limits.
- Reduced count rate in MIRI Images and MRS: see note above on ETC updates.
Opportunities
- Survey programs
Survey programs consist of similar, relatively short observations of targets drawn from a large sample; unlike GO programs, they will serve two main purposes in Cycle 4: supplementing the Long Range Plan to maintain observing efficiency if there is a shortfall of GO programs; and providing simple observations that can be executed when data volume is constrained by external factors. Survey programs have no guaranteed completion fraction. Proposals are for a number of targets, not time; proposers must specify the minimum number of targets to achieve the science goals in the Special Requirements section. See Survey Proposals for further information. NIRSpec MOS and MIRI MRS are not available for Surveys.
Artemis 2 is planned for launch during Cycle 4. Data downlink capability may be severely limited during that mission. If observing is feasible it is likely to be highly constrained.
- Targets of opportunity
Ultra-rapid and disruptive ToOs are not permitted with NIRSpec MOS.
Standard ToO proposals have a duration of one cycle. Proposers may apply for "carry-over" status if the target phenomena have a low probability of occurrence during one cycle. The proposal needs to include an estimate of the likely probability of occurrence in Cycle 4 (i.e., an annual probability). Carry-over ToOs are allowed for both disruptive and non-disruptive observations.
As with other GO categories, non-disruptive ToO proposals can request triggers in up to 2 future cycles i.e., in cycles N, N+1 and N+2. Disruptive ToO proposals are restricted to the current cycle. Future cycle ToOs are not eligible for carry-over status.
Requests for carry-over status or future cycle allocations must be justified in the APT Special Requirements and marked on the APT coversheet.
In the case of duplications, triggers from previous cycle proposals have priority.
- Joint JWST proposals
There are Joint JWST Proposal opportunities with ALMA, Chandra, HST, NASA Keck, NOIRLab, NRAO, and/or XMM-Newton. Joint JWST programs with more than one observatory are allowed. Joint proposals aim to remove double jeopardy. They should be submitted only once to the facility that represents the prime science, not to both observatories. Proposers are responsible for fulfilling all necessary requirements requested by the partner observatories. This includes noting what information needs to be submitted, meeting the deadlines for submitting that information, and ensuring that contact details are up to date. Proposers may request simultaneous observations with partner observatories, but there is no guarantee that such requests can be executed. Proposers taking advantage of Joint JWST Proposal opportunities should enter their request in the "Multi-Observatory" in the APT Proposal Information section (see instructions in the section "APT template" above). See Joint Proposals for further information.
- Future Cycles programs
Proposers may request time in up to three cycles (4, 5, and 6). Future Cycles Proposals should describe in the PDF Attachment the entire requested program and provide a cycle-by-cycle breakdown of the number of hours requested. The cycle-by-cycle breakdown also needs to be entered in the APT coversheet using the "Future Cycles” menu. If this field is not marked and filled out, the Future Cycles request might not be met, even if it is described in the proposal. The APT file should only contain the observations corresponding to the current cycle. APT files for time awarded in Future Cycles will be requested at a later time.
- Pure parallels
Pure-parallel programs may propose for observations with NIRCam imaging, NIRCam WFSS, NIRISS imaging, NIRISS WFSS and MIRI imaging (NIRSpec is not allowed as the parallel instrument). Pure parallel observations are only paired with same cycle prime programs. Due to the way that they are implemented the number of pure parallel opportunities executed cannot be guaranteed. In particular, if data volume issues are anticipated, the primary observations have priority and pure parallels are dropped. A set of Frequently Asked Questions has been added to the Pure Parallels documentation to provide clearer guidance on the current constraints on pure parallel programs.
- Super-computing
Successful JWST proposers will be eligible to apply for NASA High-End Computing (HEC) Time. Please indicate whether you intend to apply for HEC time in the text of the "Special Requirements" section of the PDF submission. More information on NASA HEC Program can be found on https://www.hec.nasa.gov.
- Citizen science with JWST
GO and AR proposals may also include a citizen science component in support of the science goals. Funded support for those activities must be compliant with the JWST General Grant Provisions and is limited to no more than 10% of the total budget. NASA document SPD-33 provides guidelines on citizen science projects.
- Laboratory astrophysics
Laboratory astrophysics relevant to JWST observations is an acceptable component of a GO proposal. Funded support for those activities must be compliant with the JWST STScI General Grant Provisions (GGP) and is limited to no more than 10% of the total budget. This component must be specified and justified in the original science proposal and may not be added subsequent to acceptance.
- Rocky Worlds Director’s Discretion Time program
The STScI Director, Dr. Jennifer Lotz, has accepted the primary recommendation of the Working Group on Strategic Exoplanet Initiatives, and has decided to proceed with a large-scale survey of rocky M-dwarf exoplanets. The program will use around 500 hours of Director’s Discretionary Time on the James Webb Space Telescope to search for atmospheres in more than a dozen nearby systems. Approximately 250 orbits of ultraviolet observations with the Hubble Space Telescope will be used to characterize the activity of the host stars. The observations will be executed by an STScI Core Implementation Team led by Dr. Nestor Espinoza, supported by Dr. Hannah Diamond-Lowe as the team Deputy. The Program is currently seeking input from the community on:
- The Targets Under Consideration (TUC) list as well as comments on the program observing strategy (due September 6, 2024). For more information on this call for input, please see the Dear Colleague Letter related to the TUC.
- Nominations (including self-nominations) to be part of the external Science Advisory Council (SAC; due August 27, 2024), whose aim is to provide advice on all aspects of the program, including target selection, data verification, and equitable community interactions. For more information on this call for nominations, please see the Dear Colleague Letter related to SAC Nominations.
The Rocky Worlds DD Team has selected the first M dwarf exoplanet targets for observation: LTT 1445 Ac (11 eclipses) and GJ 3929b (15 eclipses). The data will not be available for AR proposals in Cycle 4, but the community is encouraged to consider complementary/supplementary GO programs or associated Theory programs. The full list of potential targets is described in the Targets Under Consideration page.
- Discovery DD time proposals
This is a new type of DD proposals that is now available. Discovery Director's Discretionary Time proposals are suitable for observations of compelling scientific urgency that significantly accelerate scientific discovery. Examples of potentially appropriate Discovery DD time requests include:
- The timely follow-up of new discoveries that provide a critical link in the understanding of phenomena that would have significant impact on the broader field;
- Small-scale pilot or test observations that would have an extraordinary impact on the broader field if they were successful.
Examples of observations that are not suitable for Discovery DD time requests include:
- Observations that are a subset of larger observing programs planned for future cycles;
- Observations that are requested in order to prepare for more/follow-up observations in future cycles;
- Observations that were proposed in a recent regular proposal cycle, and were rejected, and for which the available information and/or observations have not substantially changed;
- Observations that do not have significantly compelling scientific urgency, and would therefore be more appropriately evaluated by the TAC review process during a standard observing cycle.
Discovery DD time proposals should be small, typically <10 hours in size. Unless the science is highly compelling, proposals requesting significantly more than 10 hours are generally better suited for the standard observing cycle and its TAC review process.
Next: JWST Proposal Workflow