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Hubble Space Telescope

Call for Proposals

The Call for Proposals describes the policies and procedures for submitting a Phase I proposal for HST Observing, Archival or Theoretical Research. Please read our guide to the use of electronic document formats.

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  • PDF [European A4 Size]
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DD Time

Up to 10% of the available HST observing time may be reserved for Director's Discretionary (DD) allocation.

Mid-Cycle Proposals

Up to 200 orbits per cycle will be available for Mid-Cycle GO programs. Mid-Cycle programs were initiated in Cycle 23 to provide the community with an opportunity to propose for in-cycle observations of recently-discovered, non-variable objects. As such, they complement Director’s Discretionary programs, which target unexpected transient phenomena and time-critical observations..


Scheduling Considerations