3.2 General Observer (GO) Proposals

A GO proposal may be submitted for any amount of HST observing time, counted in terms of HST orbits. Chapter 6 of the HST Primer describes how the required number of orbits can be calculated for a particular set of observations. Programs that require fewer than 100 orbits are called Regular Programs (see Section 3.2.1), and those that require 100 or more orbits are called Large Programs (see Section 3.2.2). Programs in these categories can request observing time in future cycles when this is scientifically justified (see Section 3.2.3). The additional category of Treasury Programs (see Section 3.2.4) was started in Cycle 11 to stimulate certain types of ambitious and innovative proposals that may not naturally fit in the Regular or the Large Program categories.

Proposers are strongly encouraged to develop competitive Large and Treasury proposals.

Large and Treasury proposals will be evaluated by the TAC (see Section 6.1.2), which can award up to a total of approximately 1000 orbits to proposals in these categories (approximately 1/3 of the total time anticipated to be available in Cycle 13).

Proposers of large programs should note that all HST observations are accepted with the understanding that the timescale on which the observations will actually be obtained will depend on scheduling opportunities and demands on HST resources. Experience has shown that large programs with scheduling constraints may require execution over an extended period.

In recent cycles the acceptance rate of submitted GO programs has been approximately independent of size. In general, proposals are either accepted or rejected in their entirety. Accordingly, you are urged to request the actual number of orbits required to achieve your science goals.

3.2.1 Regular GO Programs

Regular GO Programs are programs that request 99 orbits or less.

3.2.2 Large GO Programs

Large GO Programs are programs that request 100 orbits or more.

Large programs should lead to a clear advance in our understanding in an important area of astronomy. They must use the unique capabilities of HST to address scientific questions in a comprehensive approach that is not possible in smaller time allocations. Selection of a Large Program for implementation does not rule out acceptance of smaller projects to do similar science, but target duplication and overall program balance will be considered.

Proposers submitting Large programs are asked to include additional technical detail in the "Description of the Observations" section to provide information on the scheduling aspects of their program. Investigators interested in proposing Treasury/Large programs are encouraged to consult the Treasury/Large Program User Information Report (available on the Cycle 13 Announcement Page), which provides general information concerning how these programs are scheduled and summarizes technical and scheduling information that is important for these programs.

A goal in Cycle 13 is to select several programs in the 100-300 orbit range. For comparison, in Cycle 12 eight Large programs were accepted for a total of 440 primary and 500 pure parallel orbits. Descriptions of these programs are available on the HST Treasury/Large/Legacy Programs Web Page.

3.2.3 Long-Term GO Programs

Regular and Large GO Programs may request HST observing time for more than one cycle.

Long-Term Proposals must be limited to cases where it is clearly required to optimize the scientific return of the project.

Long-term programs require a long time baseline, but not necessarily a large number of HST orbits, in order to achieve their science goals. Examples include astrometric observations or long-term monitoring of variable stars or active galactic nuclei.

You may request time in as many as three observing cycles (i.e., Cycles 13, 14 and 15), but you cannot request instruments other than those presently offered in Cycle 13. Long-term proposals should describe the entire requested program and provide a cycle-by-cycle breakdown of the number of orbits requested. The scientific justification for allocating time beyond Cycle 13 should be presented in detail. For long-term programs, it is the sum of all orbits requested for Cycles 13, 14 and 15 that determines whether the program is Large or Regular. Note that we expect to replace WFPC2 during SM4.

The Cycle 13 Review Panels and TAC will be able to award limited amounts of time to Long-Term Programs for Cycles 14 and 15. GOs with approved Long-Term Programs need not submit continuation proposals in the subsequent Cycles (and hence, GOs who had Cycle 13 time approved in Cycles 11 or 12 do not have to submit a Phase I continuation proposal, although a new Phase II submission will be required).

3.2.4 Treasury GO Programs

Starting in Cycle 11, the opportunities for large-scale research with HST were expanded with the introduction of the Hubble Treasury Program. It allows proposals for datasets of lasting value to the HST program that should be obtained before HST ceases operations. A Treasury Program is defined by the following characteristics:

• The project should focus on the potential to solve multiple scientific problems with a single, coherent dataset. It should enable a variety of compelling scientific investigations.
• Enhanced data products are desirable to add value to the data. Examples are reduced images, object catalogs, or collaborative observations on other facilities (for which funding can be provided). Funding for the proposed data products will depend on their timely availability, as negotiated with the STScI Director. They should be delivered to STScI in suitable digital formats for further dissemination via the HST Data Archive or related channels.
• Data taken under the Treasury program will have no proprietary period (see Section 5.1), although brief proprietary periods may be requested, if they will enhance the public data value.

The following additional characteristics are particularly encouraged:

• Development of new techniques for observing or data reduction.
• Creation and dissemination of tools (software, web interfaces, models, etc.) for the scientific community to work with the data products.
• Inclusion of an Education/Public Outreach component. (Note that a Phase I Treasury Proposal need only summarize the planned E/PO component briefly; typically, one paragraph at the end of the Scientific Justification section. A detailed E/PO proposal should be submitted later as discussed in Chapter 11).

The emphasis in Cycle 13 remains on observations whose value is maximal if taken soon. For example, the on-orbit degradation of CCD detectors means that deep observations with ACS are of most value when obtained early in its lifetime.

Treasury programs may request observing time to be distributed in future cycles with appropriate justification (similar to the situation for Regular and Large GO programs; see Section 3.2.3). In addition, Treasury programs may request observing time in future cycles if the requested number of orbits is large enough to make implementation in a single cycle impractical or impossible.

Approximately 1/3 of the available HST observing time in upcoming cycles (approximately 1000 orbits per cycle) will be available to the combination of Large programs and Treasury Programs. For comparison, in Cycle 12 two Treasury Programs were accepted for a total of 464 primary orbits (with an additional 320 orbits in Cycle 13). The largest of these received 320 orbits in Cycle 12. Descriptions of these programs are also available on the HST Treasury/Large/Legacy Programs Web Page.

If scientifically justified, it is possible to propose a multi-cycle Treasury Program of order 1,000 orbits, with commensurate funding, to produce an enhanced dataset of high impact.

Selection of Treasury Programs will be handled by the TAC as part of the normal peer review process (see Section 6.1.2). Successful proposals will be reviewed by STScI to ensure observing efficiency. STScI resources may be made available to approved Treasury Programs by decision of the STScI Director. STScI reserves the right to conduct midterm progress reviews of Treasury Programs, to ensure that adequate progress is being made to achieve the goals of the project. Ongoing funding is contingent on the results of such reviews. For Treasury Programs above a certain cost threshold, STScI may require successful proposers to use professional project management personnel to aid the scientific team in such areas as planning, scheduling, budgeting, cost-control, and reporting.

Proposers submitting Treasury programs are asked to include additional technical detail in the "Description of the Observations" section to provide information on the scheduling aspects of their program. Investigators interested in proposing Treasury/Large programs are encouraged to consult the Treasury/Large Program User Information Report (available on the Cycle 13 Announcement Page), which provides general information concerning how these programs are scheduled and summarizes technical and scheduling information that is important for these programs.

Those interested in submitting a Treasury Proposal are encouraged to read the Hubble Second Decade Committee Treasury Program Report. The report sets out the main motivations for the Treasury Program. Following the recommendation of the HST Second Decade Committee and the recent external HST TAC review (J. Toomre, chair), the Institute Director is constituting a standing committee (Treasury Program Advisory Committee, TPAC) whose mission is to advise the Institute Director on the identification of topics for workshops to foster collaborations among interested parties and to promote discussion of science objectives and observing strategies for possible Treasury programs. As part of this process the Institute will organize workshops in the months before each annual TAC meeting to stimulate ideas, strategies, and collaborations for Treasury programs. Updates on the status of Cycle 13 will be posted on the STScI home web page, and should be visited periodically by all scientists interested in participating in Cycle 13 in any way.

Note also that the Treasury program is similar in spirit to, e.g., the SIRTF Legacy Program.

Treasury Proposals should be identified in the 'Special Proposal Types' section of the proposal (see Section 8.10).

The 'Scientific Justification' section of the proposal (see Section 9.1) should include a description of the scientific investigations that will be enabled by the final data products, and their importance. The 'Description of the Observations' section of the proposal (see Section 9.2) should not only describe the proposed observations and plans for data analysis, but should also describe the data products that will be made available to STScI and the community, the method of dissemination, and a realistic time line.