Tens of thousands of galaxies appear in this small area in Fornax (only one minute of arc across) photographed by the Hubble Space Telescope as part of a survey of the distribution of galaxies in space. It would take approximately 5 billion such images to cover the entire sky, leading to estimates that at least 50 billion galaxies comparable to or larger and more massive than ours lie within the "observable" universe. (Click on the image above for a much larger and more detailed image) (NASA, ESA, GOODS Team, M. Giavalisco (STScI), apod030625)

 An 84-hour Hubble Space Telescope exposure of a portion of the halo of M31, referred to as the Andromeda Deep Field, because of the exceptionally faint (and distant) objects revealed by the exceptionally long exposure. The image reveals stars and galaxies as faint as magnitude 31. Not long ago, the image of the globular cluster would have been an excellent one for clusters in our own galaxy. To achieve such an image in a galaxy 2 million light years away is an extraordinary accomplishment. (Click on the image above for a much larger and more detailed image) (T. M. Brown (STScI) et al., ESA, NASA, apod030519)