The Hubble Ultra-Deep Field (HUDF) is an image taken by the Hubble Space Telescope (HST) between September 24, 2003 and January 16, 2004. The target field (a 200×200-arcseconds field at Right Ascension (RA), 3h32m39.0s and Declination (dec), +27deg47m29.1s) was chosen to avoid nearby bright stars and Milky Way Cosmic Dust. Four images were made with the ACS camera, 435nm (aka, B-Band), 606nm (aka, V-Band), 775nm (aka, i-Band), and 850nm (aka, z-Band). The image has 10,000 galaxies.
A followup survey is HUDF09, images using the later WFC3 camera: 1050nm (aka Y-band), 1250nm (aka J-band), and 1600nm (aka H-band), specifically to find the highest Redshifted (z) galaxies possible: a galaxy not showing in the a Y-band image suggests a z ≥ 8 and if it also doesn't show in the J-band, a z of 10 is suggested.
Hubble Deep Field (HDF)
Ultraviolet Hubble Ultra-Deep Field (UVUDF)