Chandra's "First Light" image of Cassiopeia A was released in 1999.
NASA's Chandra X-ray Observatory is a telescope that has captured many spectacular images over its two decades of operations. Its most iconic image, perhaps, is that of supernova remnant Cassiopeia A.
Cassiopeia A or Cas A (as it is nicknamed) is the "brightly glowing field of debris" that was left behind after a massive star exploded. According to Chandra X-ray Observatory's website, this happened when the star ran out of fuel, collapsed onto itself and blew up as a supernova. Astronomers believe that Cas A, located about 11,000 light-years from, is the supernova remnant that was left behind after a star exploded in the year 1680.
"Shortly after Chandra was launched aboard the Space Shuttle Columbia on July 23, 1999, astronomers directed the observatory to point toward Cas A," says Chandra X-ray Observatory's website. "It was featured in Chandra's official "First Light" image, released Aug. 26, 1999, and marked a seminal moment not just for the observatory, but for the field of X-ray astronomy."
"20 years ago #today, Chandra's "First Light" image of Cassiopeia A was released," wrote NASA Chandra X-ray Observatory on Instagram on Monday, exactly two decades after the image was released. "Since then, Chandra has repeatedly returned to the supernova remnant to help us learn more about this fascinating object."
A new video also shows the evolution of Cas A over time. The movie shows Chandra observations from 2000 to 2013. Take a look at it below:
According to NASA, Chandra will continue to observe Cassiopeia A in the future.