Proposing with STIS

The HST General Observer proposal process is divided into two Phases. First, Phase I proposals contain a scientific justification and abbreviated technical specifications for review by the Telescope Allocation Committee (TAC) in a particular Cycle. If the Phase I proposal is accepted by the TAC, the next step is the submit a Phase II proposal. Phase II proposals provide many more technical details for programs recommended by the TAC and approved by the STScI Director for implementation.

The information required by proposers in Phases I and II is provided in several extensive documents which are linked below. These discussions also provide links to key information from those documents, to facilitate rapid access to it by proposers.

The Astronomers Proposal Tool (APT), the STIS Exposure Time Calculator (ETC), and the STIS Target Acquisition Simulator (TAS) will be of increasing utility in both Phases.

Phase I

Before creating a Phase I proposal, please check the duplication policy within the current cycle's Call for Proposals with the duplication checking tool, as duplicate observations will not be accepted.

STIS is a very versatile instrument and has a number of modes available to the user community. Because of this, we recommend taking a look at the available modes webpage, which consists of a summary of all of the available modes and some available-but-unsupported modes.

Please base orbit requests on exposure times implied by STIS sensitivity.


Phase II

The Phase II proposal requires much more specific information that the Phase I, such as which modes and gratings will be used, and how long to observe the desired target. We recommend browsing the available modes as well as the GO Wavecal Aperture Selection to help determine which modes are best for your science. A more detailed list can be found in the STIS Instrument Handbook in the Phase II Proposal Checklist. 

Because the MAMA detectors are very sensitive, they require stringent vetting in order to avoid over-saturating the detector. It is important to make sure the target is not within the same field of view as a very bright object. These limits can be found in in section 7.7 and 14.8 in the STIS Instrument Handbook


Proposing Resources

Last Updated: 01/10/2024


HST Help Desk 

Please contact the HST Help Desk with any questions.