March 11, 2020

About This Article

How do we make sure JWST will be able to make accurate science-ready measurements in Cycle 1? During science operations, the observatory will conduct an extensive calibration plan to characterize instrument and telescope performance including observations of well-understood standard stars. The calibration plan is critical for converting detector units to astrophysical quantities, to define the precise geometry of the field of view, and to monitor the health of JWST’s science instruments.

The calibration plan is intended to maximize the science that can be achieved from observations from the James Webb Space Telescope, and is informed by the science objectives of approved observing programs. The current plan builds on what has been learned during ground testing of the science instruments. The instrument teams at the Space Telescope Science Institute have worked closely with their counterparts on the Instrument Development Teams in the US, Europe, and Canada, and with NASA to coordinate and develop the plan.

While the calibration plan is based on the best available knowledge, it is also designed to be flexible. It is expected that the plan will be updated to reflect the science of the selected General Observer (GO) program, as well as any new knowledge about performance obtained during the 6-month long Commissioning phase.  

You can now explore the currently planned calibration activities. You may find the information useful in crafting your Cycle 1 proposals, in particular if you are planning to submit a proposal for additional calibrations, or if your science depends on specific elements of the calibration plan. The list includes links to the detailed definition of the calibration observations in the form of Astronomer’s Proposal Tool (APT) files and short descriptions.


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For technical assistance, please contact the JWST Help Desk.


The NASA James Webb Space Telescope, developed in partnership with ESA and CSA, is operated by AURA’s Space Telescope Science Institute.