May 3, 2024

JWST Deploys its Secondary Mirror. It’s a Real Telescope Now

The secondary mirror is on giant struts that protrude in front of the telescope. Similar to much of the telescope that needed to be folded to fit inside the Ariane 5 rocket, the secondary mirror assembly also needed to be folded and stowed. It was launched today in a slow, carefully managed procedure to position the mirror directly in front of Webbs primary mirror. The effective deploy now allows light to be directed pull back to Webbs instruments.

From left to right are: a main mirror segment, the secondary mirror, tertiary mirror and the fine steering mirror. Like the primary mirror, the secondary mirror is also covered with gold, providing them both a terrific reflective property.

JWST is presently on its method to its last location in area, the second Lagrangian point (L2) 1.5 million km (1 million miles) far from Earth. Releasing the secondary mirror comes on the heels of yesterdays substantial milestone of successfully tensioning the tennis-court-sized sunshield into its last position.
The deploy of the struts holding the secondary mirror took approximately 15 minutes, and latching those struts into location took approximately 45 minutes. Engineers at the Mission Operations Center at the Space Telescope Science Institute had the ability to verify the steps based on telemetry beamed back to Earth from the observatory.
Even with all the huge success up until now, theres little time for the Webb team to reflect and pause. Three more major deployments are required to complete Webbs preliminary commissioning: an aft instrument radiator will be extended, and the two wings of the main mirror– each one holding 3 mirror sections– need to be folded out and locked into place. If all continues to go well, these events are expected by end of week.
Lead image caption: Webbs primary mirror intercepts infrared and red light taking a trip through space and shows it onto a smaller secondary mirror. The secondary mirror then directs the light into the scientific instruments where it is recorded.Credits: IMAGE: STScI, Andi James (STScI).
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While much of the nail-biting focus has actually been on ensuring the observatorys sunshield and primary mirror release properly, a less very crucial however talked-about component of making the telescope function properly is the secondary mirror.
From left to right are: a main mirror sector, the secondary mirror, tertiary mirror and the great steering mirror. The bottom right shows an artists conception of the Webb telescope optics with its 18 primary mirror segments.
” If the secondary mirror doesnt release, you have no light through the telescope, and the mission is over,” said Dr. Heidi Hammel, an interdisciplinary researcher with the JWST task, in an interview with me in 2015, prior to the objective launched. Relatively, Hammel stated, if other parts dont release properly, there would be possible work-arounds.
, it will truly damage our mid-infrared observations, however possibly we can still do near-infrared. If the mirror doesnt totally open and you only have the center section, you lose level of sensitivity, however it might still operate.”
Nevertheless, without the secondary mirror, nothing occurs.
Contrast of telescope mirror sizes. Credit: NASA.
JWSTs secondary mirror is rather huge. Like the primary mirror, the secondary mirror is also covered with gold, giving them both a terrific reflective residential or commercial property.

Ladies and gentlemen, we have a telescope.
The secondary mirror on the James Webb Space Telescope was successfully released in space today, an incredibly important milestone.
” We are 600,000 miles from Earth and we have a telescope,” said Bill Ochs, JWST program manager, speaking triumphantly to his group after the secondary mirror was deployed and after that locked in place.

As with much of the telescope that needed to be folded up to fit inside the Ariane 5 rocket, the secondary mirror assembly also had to be folded and stowed. It was launched today in a sluggish, thoroughly managed treatment to position the mirror straight in front of Webbs main mirror. Three more significant implementations are needed to finish Webbs initial commissioning: an aft instrument radiator will be extended, and the 2 wings of the primary mirror– each one holding 3 mirror segments– need to be folded out and locked into place.