NASA's James Webb Space Telescope

Telescope and Pointing

JWST primary mirror after assembly on the backplane.
The James Webb Space Telescope's 18 mirrors are seen fully installed on the James Webb Space Telescope structure in March 2016 at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Credit: NASA/Chris Gunn

The optical telescope element (OTE) of the James Webb Space Telescope has a three-mirror design, consisting of a primary, secondary, and tertiary mirror. A fine-steering mirror provides accurate pointing and image stabilization. The design of the OTE was chosen to provide a high quality image to the integrated science instrument module (ISIM), which houses the Webb science instruments.  The links below provide information for observers about the design and performance of the telescope, the layout of the instruments in the focal plane, guiding, and image quality. Read more about the telescope...