HST Call for Proposals for Cycle 21

	Proposers to Cycle 21 should be aware that the instrument complement offered is subject to change. Please consult the Cycle 21 Announcement Webpage for up-to-date information on the status of HST instrumentation.

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A new category of GO proposal - the Medium Program - is being introduced in this Cycle (see Section 3.2.2). GO proposals will now be classified as Small (1-34 orbits), Medium (35-74 orbits), or Large (75 or more orbits) Programs based on the orbit request. Medium Programs will be reviewed by the panels and ranked together with the Small Programs. Those making the cut will proceed to the TAC, where a separate orbit pool will be available for allocation to them. This system replaces the orbit subsidy used in recent cycles, and is designed to ensure that the proposal acceptance rate is approximately independent of proposal size.

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An Ultraviolet (UV) Initiative is being introduced to ensure the unique UV capabilities of Hubble are fully utilized while they still exist. This Initiative will use orbit allocation targets to increase the share of primary GO observing time dedicated to UV observations (wavelengths < 3200 Angstroms). Small (Section 3.2.1), Medium (Section 3.2.2), Large (Section 3.2.3), and Treasury (Section 3.2.6) GO proposals are all eligible. The available UV instrument modes include ACS/SBC imaging, COS spectroscopy, STIS/MAMA imaging and spectroscopy, STIS/CCD imaging (UV gratings only) and WFC3/UVIS imaging (UV filters only). More details are given in Section 6.3.

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The UV Initiative also extends to archival proposals, in the Regular AR (Section 3.4.1), Legacy AR (Section 3.4.2), and Theory (Section 3.4.4) categories. STScI will ask the review panels and the TAC to give particular consideration to UV-specific AR proposals in the review process, provided that they lead to UV high-level data products and tools for the Hubble archive, and enable broader use of those datasets by the community. More details are given in Section 6.3.

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For Cycle 21, the focus values for the COS G130M 1055 and 1096 settings have been adjusted and now allow resolution R=λ/Δλ of between 8000 and 12000 for wavelengths between 900 and 1080 Angstroms, with an effective area comparable to that of the Far-Ultraviolet Spectroscopic Explorer. See the HST Primer and the COS Instrument Handbook for additional details.

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The STScI Director has decided to devote a significant fraction of his discretionary time to a New Frontiers program developed in response to the Hubble Deep Field Initiative. This program will involve deep imaging observations of moderate redshift galaxy clusters and offset blank fields using ACS and WFC3 operating in parallel. Further details are given at the New Frontiers website. Data taken for the New Frontiers program will have no proprietary period, and the community is encouraged to submit archival proposals for the scientific exploitation of these data. In addition, observations to supplement the discretionary time data can be proposed, as can theory programs that support the analysis of these data.

•	The right ascension (RA) restrictions that were in place for Cycle 20 no longer apply. In Cycle 21 the entire sky is accessible to HST and observations may be proposed for any sky location, subject to the standard visibility constraints of the observatory.

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Joint HST-Spitzer proposals are now available again (see Section 3.6). Up to 60 hours of time on the Spitzer Space Telescope will be awarded for joint HST-Spitzer programs in this cycle. Proposed projects must be of a fundamentally multi-wavelength nature, and both HST and Spitzer observations must be required to meet the science goals. Proposers may request up to 20 hours of Spitzer Cycle 10 time in any one HST proposal.

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As detailed in Section 10.12, NASA has the "first right of refusal" for all Hubble news releases. STScI Public Outreach news officers should be made aware of potentially newsworthy science results before the acceptance of HST publications. Proposers are reminded that STScI and NASA can provide considerable resources to support the creation and distribution of press releases.

•	Disruptive ToOs are now defined as those with turn-around times of less than 3 weeks. The number of activations of disruptive ToOs is limited to 8 in Cycle 21. There is no limit to the number of activations of non-disruptive ToOs. See Section 4.1.2 for details

•	Large GO Programs requesting 75 orbits or more in Cycle 21 must use the shorter target visibility values from Table 6.1 of the HST Primer, which will be enforced for any of these programs approved for Phase II.

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During Cycle 19, HST resurrected the capability of performing a single, linear spatial scan of the telescope relative to the target, to enable observations of very bright targets and higher S/N on other targets. This observing mode is formally offered in Cycle 21 for WFC3 only. See Section 5.5 of the HST Primer for more information on this capability.

•	Users submitting Calibration Proposals must contact the appropriate instrument group to discuss their program prior to submission (see Section 3.2.4).

•	Data taken for all Large and Treasury Programs will have no proprietary period by default. Proposers may request a proprietary period, and that request should be justified in the "Special Requirements" section of the proposal (see Section 9.3). Such a request will be subject to review by the TAC.

•	Proposers may apply for Long-Term status (up to two cycles) for Target-of-Opportunity (ToO) programs that target objects with a low probability of occurrence during one cycle (see Section 4.1.2).

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Proposers submitting Theory, Regular AR, or Legacy AR proposals (Section 3.4) are no longer required to provide a precise numerical estimate of the required budget in their Phase I proposals. For planning purposes only, the proposals should be identified as SMALL if the expected budget is less than $60,000; MEDIUM if the expected budget is between $60,000 and $120,000; and Legacy if the expected budget exceeds $120,000. As in past cycles, Legacy programs will be assessed by the TAC. The final budget for accepted programs will be assessed by the Financial Review Committee.

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We wish to remind users that HST data can be searched and obtained both through the standard HST Search Form and through the Hubble Legacy Archive (HLA). Proprietary data can only be retrieved by authorized users via the standard search form, though the outline of these observations can be displayed via Footprints in the HLA. For public data, the HLA offers a graphical search interface, image and spectral preview capabilities, mosaic combinations, enhanced data products, as well as source lists for ACS, WFPC2, and - as of this Cycle - WFC3 observations. In addition, a new Data Discovery Portal to facilitate cross-mission searches (including Virtual Astronomical Observatory access) is in development, and will become operational in early 2013.

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Investigator address information is necessary for completing an APT Phase I proposal. A web-based application, ProPer, is available for updating address information and for requesting a new user to be added to the STScI address database. ProPer has replaced use of the addr-chg@stsci.edu email address for submitting investigator address changes.

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In addition to the standard proposal categories that have existed for many cycles, STScI continues to solicit proposals in the newer categories of Treasury Programs (Section 3.2.6), Theory Proposals (Section 3.4.4) and Legacy AR Proposals (Section 3.4.2). It is also possible to request observing time on Chandra (Section 3.5), Spitzer (Section 3.6), XMM-Newton (Section 3.7), and NOAO telescopes (Section 3.8) in combination with requests for HST observations.