General Observer (GO) Proposals

A GO Proposal may be submitted for any amount of observing time, counted in hours, including all overheads. GO Proposals are classified as Small (≤ 25 hours), Medium (> 25 and ≤ 75 hours) and Large (>75 hours). Further description of these size categories can be found on Small, Medium, and Large GO Proposal Categories. The classification into these categories is the total charged time for the observatory, including overheads. Proposals in these categories can request observing time in future cycles as a Long-Term Proposal when this is scientifically justified, however the program's total time, and hence its category, will be determined from the sum total of time for all cycles in the request. The additional category of Treasury Proposals is designed to stimulate certain types of ambitious and innovative proposals that may not naturally fit into the Small, Medium, or Large Proposal categories.

There are also opportunities to apply for Joint JWST-HST observations to obtain multi-wavelength data, Survey Proposals to designate a set of scheduling-filling observations JWST can make to improve observing efficiency, and Calibration Proposals to provide calibrations for non-standard instrumentation modes. 

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 with scheduling constraints may require execution over a period that may extend into the next Cycle.

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. Laboratory astrophysics relevant to JWST observations is an acceptable component of a GO proposal. Ground-based observations that complement JWST observations may also be included as a component of a GO proposal, but note that these observations must be obtained independently, as STScI does not award time on ground-based facilities.

Next: Small, Medium, and Large GO Proposal Categories