(extremely detailed HST image of a small region of space)
The Hubble Ultra-Deep Field (HUDF) is an image
taken by the Hubble Space Telescope (HST) between September 23, 2003
and January 15, 2004.
The target field
(a 200×200 arcsecond field at
right ascension, 3h32m39.0s and
declination, +27deg47m29.1s)
was chosen to avoid nearby bright stars
and Milky Waydust.
Four images were made with the ACS camera,
435 nm (aka, B-band), 606 nm (aka, V-band),
775 nm (aka, i-band), and 850 nm (aka, z-band).
The image has 10,000 galaxies.
The HUDF was undoubtedly an effort to repeat and surpass the Hubble Deep Field (HDF)
in providing unprecedented research data.
A follow-up survey
is HUDF09, images using the later WFC3 camera:
1050 nm (aka Y-band), 1250 nm (aka J-band),
and 1600 nm (aka H-band), specifically to find
the highest redshifted 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.
Other subsequent surveys have included the field.
The HXDF (Hubble Extreme Deep Field or XDF) released
in 2012 is a portion of the HUDF.