Chapter 1 HST Phase II Proposal Instructions Introduction
The HST Phase II Proposal Instructions describe how to prepare proposals to use the Hubble Space Telescope, with the Astronomer's Proposal Tool (APT).
Boldface type indicates the name of an APT parameter or a value for a parameter.
Black text indicates an important note.
Magenta text indicates available but unsupported parameters (requires prior approval from STScI).
Red text indicates restricted parameters (for STScI use only).
Brown text indicates text file parameters.
Items in brackets - <value> - are required values.
Items in square brackets - [<value>] - are optional.
Proposals to observe with Hubble Space Telescope (HST) are reviewed in two phases managed by the Space Telescope Science Institute (STScI). In Phase I, proposers submitted an Observation Summary for review by the Telescope Allocation Committee (TAC). The Observation Summary provides only general descriptions of the targets and of the proposed observations. The TAC review results in a list of accepted proposals.
During Phase II, General Observers (GOs) with accepted proposals must provide complete details of their proposed observations so that STScI can conduct a full technical feasibility review. The Phase II information will then be used to schedule the actual observations and obtain data.
The Phase II Proposal Instructions has the following purposes:
- To describe the information that must be submitted to STScI by GOs during Phase II.
- To describe what you have to provide in APT (Astronomer’s Proposal Tool).
- To show how to submit the information to STScI.
A PDF version is available here: HST Phase II Proposal Instructions for Cycle 31
Some of the modes/parameters are not generally available to proposers, and these are indicated as follows:
- Available but Unsupported items (shown in magenta) may be used by GOs if there is strong scientific justification. In such cases calibrations will not be provided by STScI. There is limited user support from STScI for the reduction and analysis of data taken with Available-but-Unsupported modes, and that support may be provided at a low priority. Available-but-Unsupported-mode observations will be taken on a shared-risk basis, which means that observations that fail due to the use of this capability will not be repeated. Available-but-Unsupported modes can only be invoked if the Avail_Ok flag is set in the Phase II program.
- Restricted items (shown in red) generally have no valid scientific use at all and are only used for instrumental calibration and maintenance. These should never be used without the approval of an Instrument Scientist for the science instrument (SI) in question. Use these items with caution!
- Engineering text (shown in green).
To assist proposers with large programs, there is an option for proposers to export their APT file and then edit their proposal in a Text Proposal File. Text in brown has been added for proposers who elect to use this option. For guidelines on when you might use this template, see Using the Text Proposal File.
Significant Changes Since the Previous Cycle
|Ticket (Internal link)|
Ten new moons for Saturn
Enhanced documentation for Central Meridian Longitude (Solar System Observing Window)
Generic targets now require either ON HOLD or ToO Special Requirement
Add "Flexible Thursday" Target of Opportunity
Update Gyro Guiding Accuracy
Add 4 Guide Star Acquisition Scenarios to support Solar System targets and Spatial Scans
FLASHCUR and FLASHEXP now allowed then CTE is not NONE (restricted mode)
|10.2 ACS Wide Field Channel, WFC||PROPINST-91391|
Change ACS Spectro-Polarimetry from Available to Supported mode
|10.5.2 ACS WFC Permitted Filter Combinations||PROPINST-91396|
Available Science Instruments for Cycle 31
ACS/WFC, ACS/SBC, COS, WFC3, STIS and FGS are available for this cycle.
Instrument Modes, Special Requirements, etc.
Some changes have been made to these Instructions since the previous version to correct errors and omissions, and to document new modes or options. There are too many to list, but as long as you use the most recent version the information provided should reflect our current state of knowledge.
Where to Find Additional Information
As you write your Phase II proposal, you will probably need to consult the Instrument Handbooks for additional information on one or more Science Instruments. These handbooks are available on the Web and a PDF version at HST Instrument Handbooks.
There are some policies that were delineated in the Cycle 31 Call for Proposals, which asked for Phase I proposals. You may wish to review those, particularly the sections discussing limited resources.
Version Cycle 31 June - August 2023
- Started updating the Cycle number
- Added change log.
Version Cycle 30 September 2022
- Added PDF to parent page and added link to PDF from this page.
- Added change log.