In response to questions from the community, STScI clarifies that the maximum allowed visit duration, or duration of an uninterruptible sequence of visits, for Cycle 6 proposals is 6 days. This maximum visit duration is expected to be relevant only to very long Time Series Observations (TSOs). Because long observations complicate observatory operations, they will only be allowed when the proposal PDF justifies the scientific need (e.g., ultra-precise temporal monitoring). Reducing overheads is not a valid justification.

If an individual visit, or a sequence of visits, is longer than 100 hours, the Astronomer’s Proposal Tool (APT) will generate a warning ("Visit duration is too long. It... should be less than 360000.0 seconds.”) and prompt the user to explain the warning when the proposal is submitted. The response can simply be, "The maximum allowed duration is 6 days for Cycle 6 proposals.” This explanation complements the scientific justification provided in the proposal.

Make sure to check the Call for Proposals Late Breaking News section for this and other updates relevant to JWST users. Users with questions are encouraged to contact the JWST Help Desk.