The FGS, Canada's stellar navigator on the James Webb Space Telescope

Uploaded on January 28, 2022

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The FGS, Canada's stellar navigator on the James Webb Space Telescope

2022-01-28 – The James Webb Space Telescope will be the most important space observatory of the next decade, serving astronomers from all over the world.

One of the two Canadian elements on the James Webb Space Telescope, the Fine Guidance Sensor (FGS) is the most sophisticated guidance sensor of any telescope ever built. It locks on to bright stars in deep space to keep Webb's images sharp.

The FGS is crucial to the Webb Telescope. It will guide the telescope with incredible precision during all of the telescope’s observations, with an accuracy of one millionth of a degree. (Credits: Canadian Space Agency, NASA)

The FGS, Canada's stellar navigator on the James Webb Space Telescope

What is the FGS?

The Fine Guidance Sensor (FGS) is the most sophisticated guidance sensor of any telescope ever built.

It locks on to bright stars in deep space to keep Webb's images sharp.

What does the FGS do?

• Identifies and locks on to preselected guide stars
• Tracks objects in our solar system with high precision
• Keeps Webb's gaze perfectly aligned

What is it made of?

Two identical cameras that are critical to Webb's ability to “see.”

It can select a star from a catalogue of nearly one billion guide stars. These known cosmic reference points enable Webb to calculate its position in space.

When is it operational?

The FGS remains active during all of Webb's observations.

It provides Webb's stability system with extremely precise data 16 times per second.

The Canadian-made sensor is so sensitive that it can detect a tiny angular displacement equivalent to the thickness of a human hair as seen from one kilometre away.

That's like spotting someone blink in Toronto, all the way from Montreal!

Credits: Canadian Space Agency, NASA

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