Chandra X-ray

NASA

Cassiopeia A, Then the Cosmos: 25 Years of Chandra X-ray Science

By Rick Smith On Aug. 26, 1999, NASA’s Chandra X-ray Observatory opened its powerful telescopic eye in orbit and captured its awe-inspiring “first light” images of Cassiopeia A, a supernova remnant roughly 11,000 light-years from Earth. That first observation was far more detailed than anything seen by previous X-ray telescopes, even revealing – for the first time ever – a neutron star left in…