WISE

Credit: NASA/JPL-Caltech/UCLA

Observation • April 14th, 2011

This image is a map of the portion of the sky covered by the preliminary release of WISE data. WISE surveyed the entire sky in four infrared wavelengths in 2010. On April 14, 2011, the WISE team released data representing 57 percent of the sky as seen by WISE. This preliminary release will allow astronomers and astronomy enthusiasts worldwide to explore the sky as seen by WISE. It will also allow the WISE team to apply any lessons learned to the final release of the data next year that will cover the whole sky.

The sky can be thought of as a sphere that surrounds us in three dimensions. To make a map of the sky, astronomers project it into two dimensions. Various methods are used to project 3-D objects into 2-D maps, but the projection used in this image of the sky is called Aitoff, named after the geographer who invented it. It takes the 3-D sky sphere and slices open one hemisphere, and then flattens the whole thing out into an oval shape. Any projection creates distortions, so people often pick the projection type based on the where in the projection the distortions are minimal. This map is centered on the Milky Way Galaxy. The plane of the Galaxy runs along the equator, and the middle of the Galaxy is at the center of the map, where projection distortions are minimal.

The gray regions are the part of the sky not available in the preliminary WISE data release. For the regions with data, the colors used are representational: blue and cyan (blue-green) represent data from the 3.4- and 4.6-micron detectors aboard WISE, and green and red represent data from the 12- and 22-micron detectors. The blue and cyan reveals mostly light from stars, while the green and red come from mostly warm dust.

When viewing the whole sky at once in an image that fits on the typical computer screen, only the largest structures are visible, such as the band of the Milky Way itself. Nevertheless, every WISE image falls somewhere within the oval, and several regions that have appeared in WISE Featured Images are highlighted here. Clicking on the region will take you to the corresponding featured image. On the far left, in the plane of the Milky Way is the Heart and Soul nebula pair. Also, near the Heart and Soul, but beneath the plane of the Milky Way is the California nebula. Up above the plane of the Milky Way on the left is the dancing pair of galaxies, M81 and M82. The bright green nebulous area above the center of the Milky Way is the Rho Ophiuchi region. Above and to the right of Rho Ophiuchi is the Southern Pinwheel Galaxy, also known as M83. Below the center of the Milky Way Galaxy are two star clusters near and far: the Coronet Cluster and NGC 6723. On the far right, just below the plane of the Milky Way is the constellation Orion, and this weeks featured image, the Lambda Orionis Loop.