HST Preparation of the PDF Attachment
This page describes the sections required to be present in the PDF attachment. This attachment is written as a standalone file using STScI provided templates, and is uploaded through APT.
Science Justification Templates
Templates for HST Cycle 31 Proposal PDF attachments:
Note: the Word and LaTeX templates have intentionally different margins, to accommodate the same amount of text per page. See HST Guidelines and Checklist for Phase I Proposal Preparation for information on page limits.
As described in Guidelines and Checklist for Phase I, a Phase I proposal consists of a completed APT proposal form and an attached PDF file. The present chapter describes the items that must be addressed in the attached PDF file. Template files (above) are available in several popular word-processing environments for the creation of the PDF file. Your PDF Attachment should obey the page limits given in the guidelines section. There is a limit on the total number of pages, as well as on the amount of text in the ‘Scientific Justification’ section.
The entire PDF attachment must be anonymized, in accordance with the guidelines specified in HST Anonymous Proposal Reviews. Phase I proposals must itemize and briefly justify the special requirements that will be implemented in Phase II, using the Phase I section designated for this purpose.
Team Expertise and Background Section
This section should present a balanced discussion of background information, the program’s goals, its significance to astronomy in general, and its importance for the specific sub-field of astronomy it addresses. The members of the review panels will span a range of scientific expertise, so you should write this section for a general audience of scientists.
Depending on the type of proposal, the following items should also be included:
- GO Treasury, AR Legacy, and Pure Parallel Proposals should address the value to the astronomical community of the data products that will be generated by the program.
- Proposals using ACS/WFC, WFC3/UVIS, or WFC3/IR for undithered imaging must explain why this strategy is needed for the scientific objectives; dithering is required to eliminate hot pixels and other detector artifacts that may compromise the archival value of the data.
- ACS/SBC, COS, and STIS/MAMA proposers must address the safety of their targets and fields with respect to the appropriate count rate limits of the photon-counting detectors (see Chapter 5 of the Primer and the COS, STIS, or ACS Instrument Handbooks).
- SNAP Proposals should provide a complete description of the target sample.
- AR Proposals should describe how the project improves upon or adds to the previous use of the data.
- Theory Proposals should include a description of the scientific investigation that will be enabled by the successful completion of the program, and their relevance to HST.
- Calibration AR Proposals should describe what science will be enabled by the successful completion of the program, and how the currently supported core capabilities, their calibrations, and the existing pipeline or data reduction software are insufficient to meet the requirements of this type of science.
Description of the Observations
(This item is required only for GO and SNAP Proposals)
This section of the PDF file should be used to provide a short description of the proposed observations. It should explain the amount of exposure time and number of orbits requested (e.g., number of objects, examples of exposure-time calculations and orbit estimates for some typical observations). You should summarize your target acquisition strategies and durations where relevant. For CVZ targets, state the number of CVZ opportunities available in the cycle (use the Visit Planner to determine this number).
Depending on the type of proposal, the following items should also be included:
- Long-Term Proposals should provide summary information for the entire program, with a cycle-by-cycle breakdown of the requested orbits.
- Treasury Proposals should discuss the data products that will be made available to the community, the method of dissemination, and a realistic time line. It is a requirement of Treasury Programs that data products be delivered to STScI in suitable digital formats for further dissemination via the HST Data Archive or related channels. Any required technical support from STScI and associated costs should be described in detail.
- Investigators submitting Large or Treasury Proposals should discuss how they have designed their program with regard to schedulability.
- Proposers of programs with timing constraints and timing relationships between observations should describe those constraints, including allowable flexibility.
- Proposers of programs containing large blocks of orbits at constrained orientation angles, such as mosaics and surveys, should describe those constraints and allowable flexibility.
- Calibration Proposals should present a detailed justification of how they will achieve the goals of the program, and if applicable, a description of the conditions under which these goals will be achieved.
- Calibration Proposals should discuss what documentation, and data products and/or software will be made available to STScI to support future observing programs.
- Bright object protection information sufficient to establish the safety of any proposed measurements which utilize instruments subject to health and safety concerns. Programs that do not contain this information may be subject to cancellation.
(This item is required for GO and SNAP proposals)
All visit-level and exposure-level special requirements must be itemized and justified in the Phase I proposal. Generally, proposers may not add special requirements in the Phase II submission or at a later date. Special requirements include:
- For Target-of-Opportunity (ToO) observations, estimate the probability of occurrence during Cycle 31, specify whether long-term status is requested, identify whether the ToOs are disruptive or non-disruptive, and state clearly how soon HST must begin observing after the formal activation.
- CVZ observations.
- Time-critical observations.
- Early acquisition observations.
- Coordinated Parallel observations.
- Target acquisitions that use offsets.
- Scheduling of STIS/MAMA and STIS/CCD observations (other than target acquisitions) in the same visit.
- Requests for expedited data access.
- Other special scheduling requirements (e.g., requests for non-SAA impacted observations, roll-angle constraints, SHADOW, LOW SKY, etc.).
- Other special requirements (e.g. PCS MODE, GUID TOL, DROP TO GYRO, CVZ, ON-HOLD, ORIENT (ORIENT TO, ORIENT FROM, SAME ORIENT), AFTER, BEFORE, BETWEEN, GROUP WITHIN, SEQ WITHIN, PERIOD, VISIBILITY INTERVAL CORON, SEQ-NON-INT)
- For observations in support of another NASA mission, proposers should identify the mission, describe how the HST observations complement the core mission science and indicate whether any coordination is required.
- Explicitly describe and justify any scheduling requirements requiring more than 6 consecutive orbits to be scheduled together. For more information see HST Proposal Implementation and Execution.
If applicable, discuss the need for a non-default proprietary period request.
If your proposal (either GO or AR) uses a mixture of UV and optical/IR observations and you wish to claim the benefit of the UV Initiative, justify why the UV component of your proposal is essential to the science investigation.
(This item is required only for GO Proposals)
If you have plans for conducting coordinated observations with other facilities that affect the HST scheduling, please describe them here (examples are coordinated or simultaneous observations with other spacecraft or ground-based observatories). Describe how those observations will affect the scheduling.
If you have plans for supporting observations that do not affect HST scheduling, then do not describe them here. If they improve your science case, then describe them in the ‘Scientific Justification’ section of the proposal.
Joint HST-Chandra Observations
Proposers requesting joint HST-Chandra observations must provide a full and comprehensive technical justification for the Chandra portion of their program. This justification must include:
- the choice of instrument (and grating, if used),
- the requested exposure time, justification for the exposure time, target count rate(s) and assumptions made in its determination,
- information on whether the observations are time-critical; indicate whether the observations must be coordinated in a way that affects the scheduling (of either Chandra or HST observations),
- the exposure mode and chip selection (ACIS) or instrument configuration (HRC),
- information about nearby bright sources that may lie in the field of view,
- a demonstration that telemetry limits will not be violated,
- a description of how pile-up effects will be minimized (ACIS only).
Proposers should note the current restrictions on observing time as a function of pitch angle of the satellite. Refer to the Chandra Proposers’ Observatory Guide for detailed information. Proposers should check the pitch angles of their targets and be sure that any constraints they request do not render the proposed observation infeasible.
Due to increasingly challenging thermal constraints, the amount of Chandra exposure time available for High Ecliptic Latitude (HEL) targets with |bGal| > 55o is extremely limited. If you request joint time on Chandra, please avoid long exposures on such targets if at all possible. You must note explicitly the requested amount of Chandra HEL time in the body of your science justification.
Similarly, constraints that may limit the number of days your targets are observable can be difficult to accommodate within Chandra scheduling. Chandra calculates this difficulty as Resource Cost (RC). Only a fixed total number of RC points may be awarded by Chandra's joint partner observatories. Chandra makes available an RC calculator for this purpose at https://cxc.harvard.edu/toolkit/rccalc.jsp; every proposal requesting joint Chandra time should explicitly list the RC total of their requested Chandra time in the body of the science justification.
Technical documentation about Chandra is available from the Chandra X-ray Center (CXC) webpage, which also provides access to the Chandra Help Desk. The primary document is the Proposer’s Observatory Guide, available from the Chandra Proposal Information webpage. Full specification of approved observations will be requested during the Chandra Cycle 25 period when detailed feasibility checks will be made.
Proposers requesting joint HST-Chandra observations must specify whether they were awarded Chandra time in a previous Chandra or HST cycle for similar or related observations. Proposers must also specify whether the team has submitted a similar proposal in response to the current Chandra call.
Joint HST-JWST Observations
Proposers requesting joint HST-JWST observations must provide a full and comprehensive technical justification for the JWST portion of their program, including:
- the choice of JWST instrument and mode,
the requested exposure time and total time, justification for these times, target count rate(s), and assumptions made in their determination,
- information on whether the observations are time-critical; indicate whether the observations must be coordinated in a way that affects the scheduling (of either HST or JWST observations),
- any other Special Requirements, if necessary.
Technical documentation about JWST is available online.
Joint HST-NOIRLab Observations
Proposers requesting joint HST-NOIRLab observations must provide a full and comprehensive scientific and technical justification for the NOIRLab portion of their program, including:
- the telescope(s) and instrument(s) on which time is requested,
- the requested observing time per telescope/instrument, a specification of the number of nights for each semester during which time will be required, a breakdown into dark, grey and bright time, and an explanation of how the required exposure time was estimated, including information on filters, gratings, and observing conditions,
- information on whether the observations are time-critical, and whether the observations must be coordinated in a way that affects the scheduling (of either the NOIRLab or the HST observations),
- a description of any special scheduling or implementation requirements (e.g., optimum and acceptable dates).
Successful proposers will be required to provide this information in a NOIRLab Phase I proposal submitted through the standard NOIRLab process by the nominal deadline of October 2, 2023 for semester 2024A. For Gemini proposals, a Gemini PIT proposal must be submitted. For all other telescopes, the standard NOIRLab Time Allocation proposal form must be submitted. Detailed information for Gemini and other telescopes can be found in the NOIRLab Call for Proposals. Proposals not received by the deadline may not be scheduled for NOIRLab time. Successful proposers who receive time on Gemini Observatory will also have to prepare a Phase II proposal that includes a more detailed description of each observation. Submission instructions will be forthcoming following notification of the results of the HST review.
Technical documentation about the NOIRLab facilities is available from the NOIRLab webpage. Questions may be directed to the NOIRLab Proposal Help Desk by e-mail to firstname.lastname@example.org. NOIRLab will perform feasibility checks on any approved proposals.
Joint HST-NRAO Observations
Proposers requesting joint HST-NRAO observations must provide:
- the choice of NRAO telescope(s) (VLA, VLBA and/or GBT), and
- the total estimated NRAO observing time in hours.
NRAO plans to make up to 3% of VLA, VLBA, and GBT observing time available for this opportunity with a maximum of 5% in any array configuration and including an 18-month period close to the HST Cycle 31 such that all VLA configurations are available. A VLA configuration schedule is published at:
Detailed technical information concerning the NRAO telescopes can be found at:
For the VLA, joint proposals may only use capabilities defined as “general observing” in the NRAO VLA 2023B Call for Proposals, released in January 2023. Technical questions about proposing or observing for NRAO telescopes (whose answers are not found in the above links) should be posted to the NRAO helpdesk.
If approved for NRAO time, successful PIs will be contacted by the NRAO Scheduling Officers (email@example.com for the VLA/VLBA and firstname.lastname@example.org for the GBT). The successful PIs for GBT projects will be responsible for organizing the project's information in the GBT Dynamic Scheduling Software and for carrying out their GBT observations. For the VLA and VLBA, the PIs will be responsible for submitting scheduling blocks to the telescopes' dynamic queues. Projects requiring simultaneous HST-NRAO observations will be performed on fixed dates. In conjunction with HST, the NRAO Scheduling Officers will inform the PIs of those dates and times, and the PIs will be responsible for submitting scheduling blocks two weeks prior to the observations.
Joint HST-TESS Observations
Proposers requesting joint HST-TESS observations must provide a full and comprehensive technical justification for the TESS portion of their program, including:
- the suitability of using TESS survey data products,
- a justification for the selection and number of targets,
- and justification that the 120-second or 20-second cadence will sufficiently meet their science goals.
Joint HST/XMM-Newton Observations
Proposers requesting joint HST/XMM-Newton observations must provide a full and comprehensive technical justification for the XMM-Newton portion of their program, including
- the choice of prime instrument,
- the requested exposure time, justification for the exposure time, target count rates, and assumptions made in their determination,
- information on whether the observations are time-critical.
Technical documentation about XMM-Newton is available from the XMM-Newton webpage.
(This item is required only for GO Proposals)
Justify, on a target-by-target basis, any potential duplication with previously accepted observing programs. Use the ‘Duplication’ checkbox in the Observation Summary to identify the duplicating observations. See Data Rights and Duplications for policies on duplications.
(This item is required only for all AR and Theory Proposals, and GO Calibration Proposals)
All AR and GO Calibration Proposals should provide a detailed data analysis plan and describe the datasets that will be analyzed. The plan should include a brief summary of the likely scale of the proposed program, including the number of personnel and associated work effort while still following the HST Cycle 30 Anonymous Proposal Review guidelines. AR funding becomes available within 30 days of receipt of the grant PI notification letter. Any AR programs requesting a delay in the start date for funding must provide a justification as part of the Analysis Plan and the delay must be approved by the STScI Director.
Legacy AR Proposals should also discuss the data products that will be made available to the community, the method of dissemination, and a realistic time line. It is a requirement that data products be delivered to STScI in suitable digital formats for further dissemination via the HST Data Archive or related channels. Any required technical support from STScI and associated costs should be described in detail.
Theory Proposals should discuss the types of HST data that will benefit from the proposed investigation, and references to specific data sets in the HST Data Archive should be given where possible. They should also describe how the results of the theoretical investigation will be made available to the astronomical community, and on what timescale the results are expected.
Calibration Proposals should discuss what documentation, and data products and/or software will be made available to STScI to support future observing programs. Proposers should explain how their programs complement ongoing calibration efforts by the instrument groups. They should contact the relevant groups to ensure that efforts are not duplicated.