The redcircle visible in the upper left part of the image is SN 1572, often called “Tycho’s Supernova”. In the centre of the image is a star forming nebula of dust and gas, called S175 (in the Sharpless catalog of ionized nebula). This cloud of material is about 3,500 light years away and 35 light-years across. It is being heated by radiation from young hot stars within it, and the dust within the cloud radiates infrared light.
On the left edge of the image, between the Tycho supernova remnant and the very bright star, is an open cluster of stars, King 1, first catalogued by Ivan King, an astronomer at UC Berkeley. This cluster is about 6,000 light-years away, 4 light-years across and is about 2 billion years old.
Also of interest in the lower right of the image is a cluster of very red sources. Almost all of these sources have no counterparts in visible light images, and only some have been catalogued by previous infrared surveys.
All four infrared detectors aboard WISE were used to make this mosaic. The image spans an area of 1.6 x 1.6 degrees on the sky or about 3 times as wide and high as the full Moon. Color is representational: blue and cyan represent infrared light at wavelengths of 3.4 and 4.6 microns, which is dominated by light from stars. Green and red represent light at 12 and 22 microns, which is mostly light from warm dust.