This highly sophisticated map of the sky in ultraviolet radiation was made with NASAΓÇÖs Extreme Ultraviolet Explorer (EUVE). Like x-rays, most ultraviolet radiation is absorbed by the EarthΓÇÖs atmosphere, making it necessary to go to space to obtain unobstructed views of the universe in these wavelengths. The image looks peculiar because it was created with a scanning telescope. Unlike an ordinary telescope, which remains pointed toward one area of the sky, a scanning telescope moves. Ordinary sources are white dots, but larger ones, likes the EarthΓÇÖs Moon, appear as a bright row of points. The cross hair near the top center is caused by the instrument and is not a feature of the sky.
