The Hubble Space Telescope Primer for Cycle 29

The HST Primer provides an introduction to the Hubble Space Telescope for Phase I proposers.

About This Document

The Hubble Space Telescope (HST) Primer for Cycle 29 is a companion document to the Hubble Space Telescope Call for Proposals for Cycle 29. It provides an overview of HST, with basic information about telescope operations, instrument capabilities, and technical aspects of the proposal preparation process. A thorough understanding of the material in this document is essential for the preparation of a competitive proposal. The Call for Proposals discusses the policies and procedures for submitting a Phase I proposal for HST observing or archival research. Technical documentation on the instruments are available in their respective handbooks, available on the HST Document overview site.

Late Breaking News

  • April 2, 2021
    • Proposers are reminded that proposals will be assessed against the 3 primary criteria, with a separate grade given for each:
      • scientific merit within the field,
      • broader importance for astronomy & the strength of the data analysis plan (where applicable);
      • HST’s unique capabilities must also be required to achieve the scientific goals.
    • These three criteria are given equal weighting during the scoring that determines the initial ranking of proposals.
  • March 25, 2021
    • As always, proposers are encouraged to check the release notes for the HST ETC, and the known issues linked at the bottom of that page, when preparing their proposals.
  • January 21, 2021
    • Apple has recently released new Mac hardware based on Apple Silicon (M1). The APT team has discovered that the HST Orbit Planner and Visit Planner tools are not compatible with this new hardware. An upgrade is being investigated.

See also HST Cycle 29 New and Important Features.

Proposing Calendar and Deadlines

  • Cycle 29 Phase I proposal deadline: April 9, 2021 at 8:00pm EDT

  • Cycle 29 Peer Review: June 16-23, 2021

  • Cycle 29 Phase II proposal deadline: July 29, 2021

  • Cycle 29 Budget deadline: August 12, 2021 at 8:00pm EDT

  • Cycle 29 1st Mid-Cycle Deadline: September 30, 2021

  • Cycle 29 2nd Mid-Cycle Deadline: January 31, 2022

Where to Get Help

Submit questions to the HST Help Desk at See for additional tools and resources.

Who's Responsible

The HST Call for Proposals and related materials for Cycle 29 were edited by Laura Watkins. The Associate Director for Science, Neill Reid, and the Science Mission Office at STScI are responsible for the oversight of the HST science program selection process, whose members include Alessandra Aloisi (Head of Science Mission Office), John Debes (Deputy Head of Science Mission Office), Claus Leitherer (Head of Science Policies Group), Katey Alatalo, Christine Chen, Andrew Fruchter, Amaya Moro-Martin, Molly Peeples, Laura Watkins, and Technical Manager Brett Blacker.

Next: HST Cycle 29 Primer: Resources, Tools, and Other Documentation