NIRCam Long Wavelength Channel grisms as the Dispersed Fringe Sensor for JWST segment mirror coarse phasing

Fang Shi; Brian M. King; Norbert Sigrist; Scott A. Basinger

doi:10.1117/12.789641

12 July 2008 NIRCam Long Wavelength Channel grisms as the Dispersed Fringe Sensor for JWST segment mirror coarse phasing

Fang Shi, Brian M. King, Norbert Sigrist, Scott A. Basinger

Author Affiliations +

Proceedings Volume 7010, Space Telescopes and Instrumentation 2008: Optical, Infrared, and Millimeter; 70102E (2008) https://doi.org/10.1117/12.789641
Event: SPIE Astronomical Telescopes + Instrumentation, 2008, Marseille, France

Abstract

The baseline wavefront sensing and control for James Webb Space Telescope (JWST) includes the Dispersed Hartmann Sensors (DHS) for segment mirror coarse phasing. The two DHS devices, residing on the pupil wheel of the JWST's Near Infrared Camera (NIRCam) Short Wavelength Channel (SWC), can sense the JWST segment mirror pistons by measuring the heights of 20 inter-segment edges from the dispersed fringes. JWST also incorporates two identical grisms in the NIRCam's Long Wavelength Channel (LWC). The two grisms, designed as the Dispersed Fringe Sensor (DFS), are used as the backup sensor for JWST segment mirror coarse phasing. The versatility of DFS enables a very flexible JWST segment coarse phasing process and the DFS is designed to have larger piston capture range than that of DHS, making the coarse phasing more robust. The DFS can also be a useful tool during JWST ground integration and test (I&T). In this paper we describe the DFS design details and use the JWST optical model to demonstrate the DFS coarse phasing process during flight and ground I&T.

Citation Download Citation

Fang Shi, Brian M. King, Norbert Sigrist, and Scott A. Basinger "NIRCam Long Wavelength Channel grisms as the Dispersed Fringe Sensor for JWST segment mirror coarse phasing", Proc. SPIE 7010, Space Telescopes and Instrumentation 2008: Optical, Infrared, and Millimeter, 70102E (12 July 2008); https://doi.org/10.1117/12.789641

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available