The Hubble Space Telescope took its first image-a blurry, black and white one-on May 20, 1990, 25 years ago. Since that time it has provided us with many iconic images which have come to form our collective mind's eye view of the cosmos.
The first Hubble photograph showed us the binary star HD96755. Located about 1,300 light years from Earth in the open cluster NGC 3532, the image proved that the $2.5 billion Hubble could take superior images than anything else going at the time. It was, in short, a first light test.
"First light implies that the light goes all the way through the optics and makes its way to the detectors," Hubble's Deputy Project Scientist, Dave Leckrone says. "It's only when that happens that you can say first light has been achieved."
Unfortunately, first light is often dim and primitive, and it was in this case too. This was exacerbated by the famously wonky mirror which was corrected thereafter. The press and public reaction to the photograph was lukewarm at best.
"The astronomers groaned when the media was invited," Leckrone says. "And everyone was a little perplexed and uncomfortable when the image came in because it was so out of focus. Someone said 'Is that the way it's supposed to look?'"
Hubble engineers would calibrate the telescope, and they promised better pictures. Not until the December 1993 delivery of corrective optics would this promise become a reality-but eventually the Hubble produced the brilliant images we now associate with it.
For the 25th anniversary NASA shows us the explosively beautiful Westerlund 2, its image released to commemorate the event.
"Hubble has completely transformed our view of the universe, revealing the true beauty and richness of the cosmos" astronaut and associate administrator of NASA's Science Mission Directorate, John Grunsfeld says. "This vista of starry fireworks and glowing gas is a fitting image for our celebration of 25 years of amazing Hubble science."
Westerlund 2, the wonderfully illuminated centerpiece of Hubble's anniversary celebration, is a giant cluster of about 3,000 stars. Discovered in the 1960s, the cluster was named for its discoverer, Swedish astronomer Bengt Westerlund. Westerlund 2 is 20,000 light-years away from Earth in the active Gum 29 star breeding ground within the constellation Carina. The cluster contains some of our galaxy's brightest, hottest, and most massive stars, and is about 2 million years old.
Hubble's near-infrared Wide Field Camera 3 took the image by penetrating the dusty hydrogen gas cloud which enshrouds the stellar nursery. Astronomers enjoy a clear view of the nebula and its densely clustered central stars. It is between 6 and 13 light-years across the cluster, which is home to young and new stars which form as stellar winds strike the nebula's envelope of gas.
The youthful cluster allows astronomers to study a stellar nursery, gathering critical information about the formation of stars and clusters.
