James Webb Space Telescope’s First Look at Outer Space Is a Kaleidoscope of Faint Starlight
As NASA astronomers adjust its mirrors over the next month, the dots of light will eventually align into one image of a star in Ursa Major
NASA
After unfolding all 18 of its golden mirrors last month, the James Webb Space Telescope has captured its first look at starlight.
"This amazing telescope has not only spread its wings, but it has now opened its eyes," Lee Feinberg, the Webb optical telescope element manager at NASA, explained in a press conference. Like wiping your eyes after a bleary-eyed glimpse of daylight in the morning, the telescope still needs to adjust its focus.
The inaugural shot is much blurrier than the "unprecedented views of the universe" it will begin capturing when set-up is complete this summer, according to a NASA statement. Until the mirrors are fully aligned, each one is functioning as an individual telescope, explains George Dvorsky for Gizmodo. Technically, JWST captured 18 blurry images of the same star on its first go, but that's actually a great start.
“Launching Webb to space was of course an exciting event, but for scientists and optical engineers, this is a pinnacle moment, when light from a star is successfully making its way through the system down onto a detector,” said Michael McElwain, Webb observatory project scientist at NASA’s Goddard Space Flight Center.
During a 25-hour-long calibration process on February 2, the telescope collected more than 1,000 images to produce a huge mosaic with more than two billion pixels, per NASA. JWST spotted its target, which is located 260 light-years away, in just six hours.
The image NASA released last week is a small portion from the center of the massive mosaic. Each point of light in the mosaic was refracted from one of the telescope's 18 golden mirrors, but represents the same star: a bright, sun-like star called HD-84406 in the constellation Ursa Major.
The mosaic was captured using JWST's Near Infrared Camera, or NIRcam. NIRcam is able to function at higher temperatures than other instruments aboard the space observatory, so it can operate before the telescope fully cools, Gizmodo reports. Because infrared light is registers as heat, most of observatory requires cryogenic operating temperatures of negative 370 Fahrenheit or less than 50 degrees above absolute zero.
The $10 billion telescope also snagged an epic cosmic selfie with a specialized imaging lens used exclusively for engineering and alignment, not scientific observations. In the picture, one of the telescope's mirrors appears brighter than the rest in the selfie because it's pointed toward HD-84406 while the others have not fully aligned, per Gizmodo.
Astronomers will now spend the next few months shimmying each mirror until the 18 blurs align to reveal a single focused star, reports Dennis Overbye for the New York Times.
"This star was chosen specifically because it is easily identifiable and not crowded by other stars of similar brightness, which helps to reduce background confusion," NASA explains in a statement.
