The Hubble Deep Field (HDF), a picture of a tiny patch of sky taken by the Hubble Space Telescope, is the deepest optical image of the universe ever recorded. Actually, it would be more accurate to say that the HDF has captured the faintest galaxies (down to an unprecedented 30th magnitude) rather than the deepest or furthest galaxies because the distances to many of the objects are not yet known. Still, if as expected deepness goes with faintness and if thereby the image serves partly as a snapshot of the universe at a very early time in its history, then it is significant that the density of galaxies in the field is quite high; an estimated 1500 of all types and shapes crowd the frame. This would suggest that telescopically astronomers had not yet glimpsed the epoch of the first galaxies. The observations were carried out over a ten-day period in December 1995 and used four wavelength bands in order to achieve a true color image.

Exposures for the most detailed optical view of the universe were taken with the Wide Field and Planetary Camera 2 for ten consecutive days between December 18 and 28, 1995. Representing a narrow "keyhole" view stretching to the visible horizon of the universe, the HDF image covers a speck of the sky only about the width of a dime located 75 feet away. Though the field is a very small sample of the heavens, it is considered representative of the typical distribution of galaxies in space because the universe, statistically, looks largely the same in al directions. Gazing into this small field, Hubble uncovered a bewildering assortment of at least 1500 galaxies at various stages of evolution.