The European Space Agency's XMM-Newton space telescope has been in orbit since 1999, and it's constantly collecting information, even when it's just adjusting its position. This picture, a composite of more than 73,000 images, shows what happens when the telescope moves across the sky as it focuses its attentions from one object to another, leaving a slew of x-ray data in its path.
It kind of looks like a giant orange broom, but that big, bright dot on the right is the Vela supernova remnant, one of the largest features in the sky visible by x-ray. In the center, you can see Scorpius X-1, the strongest source of x-ray emissions in the sky apart from the Sun.
A full catalog of XMM-Newton's slews can be accessed here.