X-ray vision
The X-ray observatories XMM-Newton (left) and Chandra have allowed astronomers to study neutron stars in more detail than ever before. The two satellites, which are run by ESA and NASA, respectively, were launched in 1999 and orbit the Earth once every 48 and 68 hours. They are equipped with powerful X-ray telescopes plus instruments such as CCD cameras and spectrometers that measure the intensity and energy of the X-rays. Credit: ESA (left) and NASA.