Panning on the Hubble Deep Field from 1995

Piero Rosati, European Southern Observatory explains about Deep Fields in general:

?The first Hubble Deep Field was in 1995. When this experiment was first proposed ? an experiment consisting of staring at the same patch of sky for weeks ? nobody really knew if this would lead to any interesting scientific results. But when we first looked at the imaged we were astonished! We could see more than 3000 galaxies in this small field. We could definitely tell that the Hubble Deep Field opened a whole new era of observational cosmology. Just forming our view of the distant universe?.

Credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)