The spiral galaxy NGC 7331 [right] has sometimes been referred to as a twin of the Milky Way due to its similar size and shape. Discovered by English astronomer Sir William Herschel in 1784, the galaxy lies some 50 million light-years away in the Pegasus constellation. (The galaxies in the center of the image appear smaller because they are much farther away.) This crisp new color-filtered image from Calar Alto Astronomical Observatory in southern Spain was made by pointing that observatory’s largest telescope, with an aperture of 3.5 meters, at NGC 7331 for more than two hours over multiple exposures. The galaxy's angle as viewed from Earth allows astronomers to peer along its disk and gives images such as this one their rich sense of depth.