STScI solicits proposals for JWST Observing, Archival, and Theoretical Research. Downloadable PDF collections of these articles are provided as a courtesy, made available and updated when feasible.

Late breaking news

New information that arises during the Cycle 4 Call for Proposals will be provided here.

• Make sure that you create the PDF using the latest version of the .sty file. The .sty file was updated 09/17/2024 to use /normalsize for the figure captions. The latest update on 10/10/2024 provided further clarification regarding which headings are optional. The font of the captions will still appear slightly smaller than the text. That is fine, do not change the .sty file.

• 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.  

• 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 are described on the Targets Under Consideration page.
  

• Proposers updating Multi-Observatory proposals from Cycle 3 for resubmission in Cycle 4 should read this Knowledge Article to get started.

• Important notice for proposers with Windows machines: APT 2024.5.2 is now available in the APT page and patches the Windows specific file saving problem in APT 2024.5.1. 

• Cycle 4 proposers should now download the Astronomer's Proposal Tool (APT) version 2024.5.1 or higher for proposal preparation, released on August 22, 2024. Details can be found in the release notes (for current and past versions).  

• Cycle 4 proposers should use the JWST Exposure Time Calculator (ETC) version 4.0, released on July 29, 2024. See the release notes for details, and be sure to review the known issues for this version. 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.

Welcome

We invite scientists to participate in Cycle 4 of the James Webb Space Telescope (JWST) operations. The telescope and its instruments were built under the auspices of the National Aeronautics and Space Administration (NASA), the European Space Agency (ESA), and the Canadian Space Agency (CSA). Management of JWST's scientific program is carried out by the Space Telescope Science Institute (STScI). We anticipate allocating up to 8,500 hours in this cycle. Prime time allocation in Cycle 3 consisted of 43% for Small programs (≤ 25 hours), 35% for Medium programs (> 25 and ≤ 75 hours), and 22% for Large programs (> 75 hours). For Cycle 4, the proposal size boundaries have changed. 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. Abstracts of previously accepted programs can be found on the JWST proposal catalogs webpage.

This document establishes the goals, requirements, and policies for General Observer (GO) and Archival Research (AR) programs in Cycle 4. The table of contents for the web version of this document is on the left side of this page, and links there can take you to any page from any other page (click the arrow to expand the entire table of contents under "JWST Call for Proposals for Cycle 4"). The links at the top of each page correspond to sections within that given page.

Proposing calendar and deadlines

Cycle 4 observing dates: July 1, 2025 – June 30, 2026

Cycle 4 proposal deadline: October 16, 2024 by 8:00pm US Eastern Daylight Time

Cycle 4 Peer Review meeting: February 3 - February 14, 2025

Cycle 4 Budget submission deadline: April 10, 2025 by 5:00pm US Eastern Daylight Time

Notification of the outcome of the selection process will be sent to all proposers in early March, 2025.

Where to get help

• Read all sections of this Call for Proposals by following the Table of Contents (left side of the web version). 
• Visit the STScI JWST Proposal Workflow
• Visit the JWST User Documentation Homepage (on this website).
• Register (or update) a STScI Single Sign-On (SSO) Account
• Contact the STScI JWST Help Desk. We strongly encourage users to use this avenue to submit questions directly to the appropriate team of experts.

Who's responsible

The JWST Call for Proposals and related materials for Cycle 4 were edited by Amaya Moro-Martín. The Associate Director for Science, Neill Reid, and the Science Mission Office at STScI are responsible for the oversight of the JWST science program selection process, whose members include Marc Postman (Head of Science Mission Office), Katey Alatalo (Head of James Webb Space Telescope Science Policies Group), Christine Chen, Andrew Fruchter, Amy Jones, Susan Kassin, Claus Leitherer, Nikolay Nikolov, Amaya Moro-Martín, Molly Peeples, Jamila Pegues, Linda Smith, Laura Watkins, and Technical Manager Aleksandra Hamanowicz.

Next: JWST New and Important Features