APOD 2.1

This week's focus picture is an Ultraviolet image of the Andromeda Galaxy. The Andromeda galaxy is the closet Spiral Galaxy to our own, and is visible in our own night sky as M object 31, located in the constellation Andromeda. 

Andromeda Galaxy as viewed in the normal spectrum

The purpose of taking Ultraviolet images is to detect the hottest and brightest objects in the night sky, which might not be discernible through normal optical viewing. You can compare the Optical image (above) to the Ultraviolet image (below). The comparison should reveal concentrated points of light and heat emission, which are the youngest, hottest, and brightest star of the Andromeda galaxy.

Ultraviolet Andromeda

These images are incredibly high resolution, and that's because they are a compilation of over 330 different shots all meshed together to give us this picture. In it's unaltered form, the picture has a digital file size of 85GB. For those who don't know, that's a LOT. The picture also took over 10 weeks to compile. The shots were taken by the Swift satellite, a satellite normally dedicated to taking pictures of novas.