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The Hubble Space Telescope (HST) proposal process involves various
steps, which are summarized below. For more details please check this page.
Call for Proposals
Call for Proposals (CP) invites the astronomical community to
propose for observing time on HST in a given cycle (nominally one year
in duration). It summarizes the policies and procedures for
proposing in that cycle of HST observing, including requests
for funding research on archival HST data.
A CP for a given cycle is issued approximately a year before the
nominal start of the cycle.
Phase I: Writing and submitting a proposal for HST observing time
The CP describes in detail the policies and procedures for submitting a Phase
I proposal for HST. Proposers should also consult all relevant technical documentation about the
capabilities and sensitivities of the instrument(s) to be used in their
programs and should discuss the requirements of their observing programs with
appropriate Space Telescope Science Institute (STScI) experts. Contacts are
provided via the STScI Help Desk at
firstname.lastname@example.org. To avoid duplication
conflicts proposers also should consult up-to-date exposure ASCII catalogs and the Duplication Checking Web Form.
Phase II: Providing the details
A Telescope Allocation Committee (TAC), organized by the STScI, reviews and
evaluates the submitted Phase I proposals. The TAC recommends a list of
programs to the STScI Director for preliminary approval and implementation.
Upon final approval by the Director, a successful proposal enters into the Phase II stage of proposal
preparation, during which proposers must
provide the details required by the ground system to schedule HST and obtain
Most HST observations have proprietary periods of one year, during
which the data are only accessible to the proposers. More details on HST
proprietary rights are available.