Two months after a dramatic Christmas morning launch and several chilling weeks of spinning and unfolding, the James Webb Space Telescope has achieved what astronomers celebrate as “first light.”
Actually, it was the first lights.
NASA released 18 images Friday of a star in the constellation Ursa Major, known as HD 84406, as seen through each of the 18 segments that make up the telescope’s primary mirror and recorded by the Webb’s workhorse instrument, the Near Infrared Camera (NIRCam). ). Over the next few months, Webb’s astronomers will wiggle each of those mirror segments back and forth until that star becomes one.
Marcia Rieke, a professor of astronomy at the University of Arizona who led the team that built NIRCam, described the Webb team as “ecstatic” in a NASA press release.
The Webb telescope is a joint effort of NASA, the European Space Agency and the Canadian Space Agency that has been 25 years and $10 billion in the making. Named after a former NASA administrator who led the space agency through the early Apollo years, the spacecraft is a successor to the Hubble Space Telescope. It was designed to study the universe when it was only about 200 million years old and the earliest stars and galaxies were just emerging from the misty remnants of the Big Bang. It will also study the secrets of black holes and examine exoplanets around nearby stars for signs of habitability or life.
To that end, the instruments are designed to be sensitive to infrared or “heat” radiation. Because the light waves from such distant objects are stretched in an expanding universe, they can only be registered in longer electromagnetic wavelengths than human eyes or normal sensors can see.
The Webb is now parked about a million miles from Earth, orbiting the sun behind a silvery foil heat shield that keeps it cold enough for the telescope to sense the distant heat of planets and galaxies.
As a “first light” bonus, a camera on the NIRCam took a picture of the mirror array itself — the best look at the spacecraft anyone has gotten since shortly after it left Earth.
The telescope’s first scientific results are expected this summer after all the fiddling and focusing is done. The universe should be getting ready for its close-up.