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Reminder: Cycle 25 Mid-Cycle Observations with HST: March 21 Deadline

Proposers are reminded of the upcoming deadline for Mid-Cycle GO proposals. Mid-Cycle GO proposals must meet the following prime criteria:
  1. Proposers must provide an explanation of why the proposal could not have been submitted in response to the standard annual Call for Proposals: for example, the target source may have been identified subsequent to the most recent proposal deadline.
  2. Proposers must provide a clear description of the scientific urgency of these observations and why they should be executed in the present cycle.

    1. Mid-Cycle GO proposals will also have the following characteristics:
      1. Proposals are limited to requesting no more than 10 orbits;
      2. Observations should have minimal constraints to maximize scheduling flexibility;
      3. Observations taken for accepted programs will have a proprietary period of no more than 3 months;
      4. Proposals may request only HST time - joint proposals are not permitted;
      5. Proposers may apply for all available instruments. Proposals must be compliant with the technical restrictions described in the Cycle 25 Call for Proposals.
        1. Proposal Submission and Review
          Proposals should be submitted via the Astronomer’s Proposal Tool (APT) as type GO, using the Mid-Cycle template for the pdf attachment. Proposals may be submitted by 23:59 pm on March 21, 2018; The proposals will be distributed for review by members of the community, with the results released by mid-May.
          Full details are found at:

          Observations of Plumes on Europa

          Call for Europa Proposals

          STScI is also issuing a call for observing programs aimed at detecting outgassing from Jupiter’s satellite Europa. A priority target for a NASA Flagship Mission, observations obtained with Hubble show evidence for activity suggestive of outgassing from the sub-crustal ocean. There is high scientific importance in learning more about potential Europa plumes, their properties and locations. Following the recommendations of a small advisory committee (John Clarke, Boston University, chair; Amanda Hendrix, Planetary Science Institute; John Spencer, Southwest Research institute), the STScI Director is making up to 50-100 orbits available for observations directed towards this purpose during the 2017/2018 Jupiter apparition. The submitted proposals must be aimed specifically at detecting plume activity. In that context, the community’s attention is drawn to recent observations taken with STIS (GO 15371) that are designed to measure the level of scattered light in proximity to Jupiter. The Europa proposals are not subject to the size and scheduling restrictions associated with Mid-Cycle proposals. Proposals may only request time with HST; joint proposals with other facilities (Chandra, XMM, NOAO) are not permitted. The default proprietary period for these proposals is 6 months.

          Proposal Submission and Review
          Proposals should be submitted via the Astronomer’s Proposal Tool (APT) as type GO, using the Cycle 25 template for the pdf attachment. Proposals must be submitted by 23:59 pm on September 30, 2017. The proposals will be distributed for review by members of the community, with the results released by early November.

          The following reports have been provided for your information. Europa Advisory Committee Report and Background light measurements near Jupiter: GO 15371, summary report.


          Following peer-review, observing time has been awarded to three proposals:
          • GO 15419 Abundance, composition, and variability of Europa's plumes: Pathfinding future habitability investigations (PI Lorenz Roth)
          • GO 15424 An intensive ultraviolet imaging campaign for Europa's plumes (PI William Sparks)
          • GO 15425 Eclipse Observations of Europa's Water Plumes (PI Katherine de Kleer)

          Enhanced HST Schedule Gap Program

          Call for Proposals

          STScI is pleased to announce the opportunity to propose target lists for the “Schedule Gap” program. Starting in Cycle 24, STScI has been scheduling ACS observations to make use of those orbits in which normal GO or SNAP observations cannot be scheduled. In the first 10 months, Program 14840 has obtained observations of 97 galaxies – approximately 10 observations per month. This pilot project uses a catalog of 500 NGC galaxies and obtains two dithered ACS Wide Field Camera F606W 337 second exposures for each target. Targets are selected late in the construction of the weekly HST schedule after all other opportunities are exhausted. As portions of the sky have become “exhausted”, the F814W has recently been added to this program.

          The report of the November 16, 2016 meeting of the Space Telescope Users Committee recommended:
          “The STUC supports the new Schedule Gap program, and encourages the STScI to consider additional factors without adding extra work in scheduling, including (i) additional source catalogs or additional filters in the current program; and (ii) opportunities to engage the public to provide targets for EPO purposes.”

          At this time we are soliciting proposals for additional source catalogs and/or creative advice in using this scheduling opportunity. Proposers should be aware that this lowest priority scheduling has multiple restrictions. These include: (1) limiting the visit duration to ~25 minutes or less, (2) being broadly distributed on the sky, (3) use of ACS/WFC only, (4) no opportunity for changes in the proposal after the start of execution, and (5) no observatory level special requirements (e.g. ORIENT). STScI will make these data non-proprietary and funding will not be provided. It is not possible to predict in advance what fraction of the catalog will be observed, when the observations will occur, or which objects will be selected for observation.

          To propose, a two page PDF file should be sent to no later than September 12, 2017. The proposal should briefly explain the scientific motivation for the observations, their value within the larger context of the HST archive, the basic parameters of the proposed source catalog (e.g. number of objects, types of objects, range of apparent magnitudes, sizes, distribution on the sky, etc. – a complete and final list is not required at this time). Basic observing parameters should also be specified (filters, exposure time, number of exposures, etc.) The proposals will be evaluated by a panel that will provide recommendations to the STScI Director. The successful proposer(s) will be expected to submit an APT file in consultation with STScI staff.

          Questions may be directed to for policy or technical issues.


          Following Review, the following three proposals were awarded:
          • GO 15444 An ACS Schedule Gap Imaging Survey of Nearby Active Galaxies (PI Aaron Barth)
          • GO 15445 Gems of the Galaxy Zoos (PI William Keel)
          • GO 15446 Establishing HST's low redshift archive of interacting systems (PI Julianne Dalcanton)

          Fundamental Physics with HST

          Over the last three decades the Hubble Space Telescope has played a crucial role in probing key parameters relevant to fundamental physics and cosmology. The H(0) key project figured prominently in during the early years, and subsequent programs have reduced measurement uncertainties to less than 3%. More recently, Hubble has investigated other parameters, including testing the nature of dark matter through observations of merging galaxy clusters and using white dwarf spectra to constrain the gravity dependence of the fine structure constant.

          Looking forward, the STScI Director convened a working group drawn from the physics and cosmology communities to provide advice on how Hubble might contribute to future investigations in fundamental physics. The committee was chaired by Prof. Bhuvnesh Jain (University of Pennsylvania), and included Prof. Neal Dalal (University of Illinois), Professor Cora Dvorkin (Harvard University), Prof. Jeremy Heyl (University of British Columbia), Prof. Marc Kamionkowski (Johns Hopkins University), Dr. Phil Marshall (SLAC National Accelerator Laboratory), and Prof. David Weinberg (Ohio State University). The committee consulted with members of the community and submitted a final report in November 2017.

          The Charter can be found here as well as the Final Report.

          Cycle 25 Long Range Plan has been Released

          As announced in the Cycle 25 Call for Proposals, the programs accepted by the Cycle 25 TAC will be implemented over an 18-month nominal duration, extending into Cycle 26. In addition, there is a Cycle ‘tail' that can extend a further 6 months for observations having restrictive scheduling constraints or subscription conflicts with other activities in the nominal Cycle period. The current Long Range Observing Plan is fully subscribed through at least April 2019. A large fraction of the observations are highly constrained and therefore have limited flexibility for when they can be executed. We know that some PI’s with observation plan windows in 2019 will be disappointed that their data cannot be obtained sooner. However, please be aware that every effort has been made to ensure maximum efficiency and equitable use of the observatory on behalf of the HST community.

          Please also be aware that the Long Range Plan is continually evaluated to ensure that observatory efficiency remains as high as possible. Changing science and observatory events may open up opportunities for us to move observations forward in the plan. HST planners are vigilant to identify observations that can take advantage of those opportunities and move them early whenever possible. Beyond that, PIs may submit requests to the Telescope Time Review Board (TTRB) for changes in program execution plan windows, but only with a strong scientific justification for doing so. Thank you for your understanding and patience.

          Announcement Notice

          NASA and The Space Telescope Science Institute (STScI) are pleased to announce the Cycle 25 Call for Proposals for Hubble Space Telescope (HST) Observations and funding for Archival Research and Theoretical Research programs. Participation in this program is open to all categories of organizations, both domestic and foreign, including educational institutions, profit and nonprofit organizations, NASA Centers, and other Government agencies.

          Cycle 25 will extend from October 1, 2017 to September 30, 2018. We will accept proposals for the following instruments: ACS, COS, FGS, STIS, and WFC3.

          This solicitation for proposals will be open through April 07, 2017 8:00pm EDT. The Astronomer's Proposal Tools (APT), which is required for Phase I Proposal Submission will be made available/released for Cycle 25 Phase I use during the last week of January 2017. Results of the selection will be announced by the end of June 2017.

          Please see the Cycle 25 Announcement page for detailed information.

          Mid-Cycle Proposals

          NASA and Space Telescope Science Institute (STScI) are pleased to announce a new opportunity to apply for observations with the Hubble Space Telescope. Mid-cycle proposals aim to allow the community to follow up on discoveries made since the Cycle 23 proposal deadline. Participation in this program is open to all categories of organizations, both domestic and foreign, including educational institutions, profit and nonprofit organizations, NASA Centers, and other Government agencies. Proposals are limited to no more than 10 orbits. Full details are given at the above link.

HST Frontier Fields

Using Director's Discretionary (DD) observing time, HST is undertaking a revolutionary deep field observing program to peer deeper into the Universe than ever before and provide a first glimpse of JWST's universe. These Frontier Fields will combine the power of HST with the natural gravitational telescopes of high-magnification clusters of galaxies. Using both the Wide Field Camera 3 and Advanced Camera for Surveys in parallel, HST will produce the deepest observations of clusters and their lensed galaxies ever obtained, and the second-deepest observations of blank fields (located near the clusters). These images will reveal distant galaxy populations ~10 - 100 times fainter than any previously observed, improve our statistical understanding of galaxies during the epoch of reionization, and provide unprecedented measurements of the dark matter within massive clusters.

Data releases of the already observed clusters are available at the MAST Frontier Fields website.

The Frontier Fields public lensing models have been released and are available on the MAST Frontier Fields Lensing Model website. This website includes interactive tools for examining the lensing maps and obtaining magnifications and uncertainties from a variety of models, given a position and redshift.

For more information about the survey, please see the Frontier Fields website.

Frontier Fields Lensing Map Call for Proposals

Frontier Fields CP document

We are soliciting gravitational lensing maps for the last four Hubble Frontier Fields clusters (MACSJ0717.5+3745, MACSJ1149.5+2223, AbellS1063, and Abell 370) based upon the exceptionally deep HST FF imaging and other new ancillary data. Previously unsupported teams may also apply to create gravitational lensing maps for Hubble Frontier Fields clusters Abell 2744 and MACSJ0416.1- 2403 if those teams provide a substantially different model set from existing models.

For the full set of proposal instructions and requirements, see the FY16 Frontier Fields Lensing Map Call for Proposals. All proposals are due 5:00PM EST, February 4, 2016. Proposals may be submitted electronically to Cheryl Schmidt in the STScI HST Mission Office. Questions about this request for proposals or the HST Frontier Fields should be sent to Dr. Helmut Jenkner.

Exposure Time Calculators

The ETCs are web-based applications that assist Hubble users in preparing Phase I and Phase II observing proposals. The ETCs calculate exposure times or SNRs for simulated astronomical observations using any of HST's primary instruments:


Program Status

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