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Project scientist Mark Clampin is reflected in the mirror segments of the James Webb Space Telescope during testing. (Image by Ball Aerospace)

The astronomy community breathed a collective sigh of relief as the James Webb Space Telescope (JWST) reached a major milestone. When the final primary mirror segment unfolded and latched into position at 1:17 p.m. on Jan. 8, the JWST mission team declared all major components of the recently launched space telescope successfully deployed.

The gold-plated primary mirror, which is 21 feet in diameter, is comprised of 18 mirror segments, each of which must now be moved into position to align the telescope optics. 126 independently controlled actuators on the back of the primary mirror will move the mirror segments into the precisely aligned configuration needed to obtain sharp images.

The secondary mirror must also be properly aligned in a process well known to terrestrial astronomers. Collimation is the process of aligning telescope optics to achieve the best image resolution and clarity. I have spent dozens of hours engaged in this process with my own telescopes and know that it can be a difficult and sometimes-frustrating task.

To execute the same process by remote control on a vastly more complicated and sensitive instrument located 1 million miles away in interplanetary space is yet another example of the audacity with which progress is made. The peaceful exploration of space brings out the best in us and demonstrates what we are capable of as a species.

The deployment and commissioning of the telescope is incredibly complicated. The unfurling and tensioning of the 70-foot-long sunshield assembly alone involved 140 release mechanisms, 70 hinge assemblies, 400 pulleys, 90 cables totaling 1312 feet, and various springs, gears and motors. The deployment of the sun shield concluded on Jan. 4.

Once the lengthy alignment and commissioning process are completed sometime this summer, the telescope will begin to explore everything from worlds in our own solar system to objects formed soon after the big bang.

JWST will peer into the infrared wavelengths of the electromagnetic spectrum, returning images of the earliest galaxies. These galaxies, which formed more than 13 billion years ago, are some of the oldest structures in the universe.

Are we alone in the universe? The JWST may even answer one of the most profound questions of our time. With its ability to perceive the chemical elements and compounds present in exoplanet atmospheres, JWST may reveal compelling evidence for the presence of life on alien worlds.

The Morning Sky

Mars is up in the eastern morning sky, low but distinct in the hours just before sunrise. Venus is rushing back into view, emerging on the other side of the sun from our perspective and entering the morning sky. By early next week, Venus will rise in the east more than an hour before the sun.

The Evening Sky

The moon is full on Monday night. Whenever the moon is full, it rises in the east just as the sun sets in the west. Mercury is getting tougher to spot low in the west after sunset as it heads back toward the sun on its 88-day orbit. Saturn is also sinking lower in the west. For comparison, Saturn is 30 times farther from the sun than Mercury and takes 29 years to orbit once around the sun. The brightest object in the western sky after sunset, Jupiter is still an easy catch.

Dan Price is a NASA/JPL Solar System Ambassador and informal educator. He leads the Night Sky Tours at Josephine Sculpture Park. Have a question about astronomy or space science? Send an email to dan@starpointestudio.com and it might be featured in a future column.

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