HST Cycle 26 New and Important Features

The Hubble Space Telescope Cycle 26 Call for Proposals differs from Cycle 25 and other previous cycles in the following ways.

What's New for Cycle 26

Proposers to Cycle 26 should be aware that the instrument complement is subject to change.

  • Proposals must now be submitted and reviewed in an anonymous format. See HST Cycle 26 Anonymous Proposal Reviews for more information on the review process. Guidelines are provided on how to anonymize a proposal.
  • Regular Small GO Proposals are not solicited. The Cycle 25 TAC pre-allocated 1200 orbits of Cycle 26 observing time. We anticipate allocating up to 2100 additional orbits in this ΔCycle 26 Call for Proposals for Medium, Large, and Treasury programs. Small Joint proposals with other observatories will be accepted. Legacy Archival proposals will also be accepted. Regular Small GO, Regular Archival, Regular Calibration, Regular AR Theory, and Snapshot Proposals were solicited as part of the Cycle 25 Call and will not be accepted. Proposals for Mid-cycle time and Director's Discretionary time are still welcome, provided they meet the criteria of each program.
  • The review process will be divided into four sub-panels, rather than the seven from previous years.
  • Proposers must also submit a brief "Team Expertise and Background" section via email to STScI. This section will be revealed to the review panel after the final ranked list is made, at which point, the review panel may disqualify proposals that are not sufficiently poised to carry out the proposed work. See also HST Cycle 26 Anonymous Proposal Reviews.
  • Fundamental Physics with HST: STScI encourages proposals that tackle questions in fundamental physics, particularly as highlighted in the 2017 report from the Fundamental Physics Working Group. These proposals can be for observations (GO) or archival research (Legacy AR). Given the limited resources available in Cycle 26, proposers may consider pilot investigations that could be expanded in future cycles. The proposals will be reviewed by experts in the appropriate field.
  • Phase I proposals must include in their description of observations 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.
  • Phase I proposals that are awarded observing time will be held to a strict deadline for subsequent Phase II and budget submissions.  Programs that submit Phase II proposals that are either late or insufficient for long-range planning will be subject to cancelation.  Programs that submit late budgets may not receive funding.
  • Phase I proposals must itemize and briefly justify the special requirements that will be implemented in Phase II. Specifically, all visit-level special requirements and exposure-level special requirements must be justified (see HST Cycle 26 Preparation of the PDF Attachment).
  • All non-proprietary data for current Hubble instruments (ACS, COS, STIS, WFC3, FGS) have been made available as part of the Amazon Web Services (AWS) public dataset program. Proposers may request to make use of this dataset under the archival legacy category.
  • Two new central wavelength settings are being offered this cycle for COS/FUV observations, named G140L/800 and G160M/1533. The G140L/800 setting allows for contiguous coverage of the entire spectral region from 800 to 1950 Angstroms on a single COS detector segment (FUVA) with a low spectral height below 1150 Angstroms, allowing higher S/N for background-limited observations. The G160M/1533 setting extends coverage at the short-wavelength end of G160M by 44 Angstroms to overlap with the longest wavelengths covered by the G130M/1222 setting, and is otherwise expected to be very similar to the existing G160M/1577 cenwave. This allows a broad range of FUV wavelengths to be covered by just two central wavelength settings (1222+1533). For full details, see the COS Instrument Handbook.
  • The COS team has introduced new, lower S/N requirements for NUV acquisition images (ACQ/IMAGE exposures). ACQ/IMAGES with the primary science aperture (PSA) now need to reach S/N=20 (vs 40 previously), and those with the bright object aperture (BOA) need reach S/N=30 (vs 60 previously). These changes will result in shorter acquisition times. COS users should consider the new lower overheads when calculating their orbit requests. For full details, see the COS Instrument Handbook.

Next: HST Cycle 26 Anonymous Proposal Reviews

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