Hubble Ultra Deep Field

The Hubble Ultra Deep Field, or HUDF, is an image of a small region of space in the constellation Fornax, composited from Hubble Space Telescope data accumulated over a period from September 24 2003 through January 16 2004. It is the deepest image of the universe ever taken in visible light, looking back approximately 13 billion years, and it will be used to search for galaxies that existed between 400 and 800 million years after the Big Bang. [cite web |url=http://hubblesite.org/newscenter/archive/releases/2004/07/text/ |title=Hubble's Deepest View Ever of the Universe Unveils Earliest Galaxies |publisher=Space Telescope Science Institute |accessdate=2008-09-02]

The HUDF image was taken in a section of the sky with a low density of bright stars in the near-field, allowing much better viewing of dimmer, more distant objects.The image contains an estimated 10,000 galaxies [ [http://hubblesite.org/newscenter/archive/releases/2004/07/ The image yields a rich harvest of about 10,000 galaxies.] ] . Although most of the targets visible in the Hubble image can also be seen at infrared wavelengths by ground-based telescopes, Hubble is the only instrument which can make observations of these distant targets at visible wavelengths.

Located southwest of Orion in the Southern-Hemisphere constellation Fornax at right ascension 3h 32m 40.0s, declination -27° 47' 29" (J2000), the image covers 11.5 square arcminutes. This is just one-tenth the diameter of the full moon as viewed from Earth,smaller than a 1 mm by 1 mm square of paper held 1 meter away, and equal to roughly one thirteen-millionth of the total area of the sky. The image is oriented such that the upper left corner points toward north (-46.4°) on the celestial sphere. The star near the center of the field is USNO-A2.0 0600-01400432 with apparent magnitude of 18.95.

In total, the image required 800 exposures taken over the course of 400 Hubble orbits around Earth. The total amount of exposure time was 11.3 days for the ACS and 4.5 days for the NICMOS.

ee also

*Hubble Deep Field
*Hubble Deep Field South

External links

* [http://hubblesite.org/newscenter/newsdesk/archive/releases/2004/07/text/ Hubble's Deepest View Ever of the Universe Unveils Earliest Galaxies] - NASA press release
* [http://www.nasa.gov/vision/universe/starsgalaxies/hubble_UDF.html NASA site with animations]
* [http://hubblesite.org/newscenter/newsdesk/archive/releases/2005/28/full/ Exploring galaxy formation in the early universe] - How did the first galaxies get so large so quickly?
* [http://www.wikisky.org/?img_source=IMG_all&zoom=13&ra=3.54417&de=-27.7914 Scalable interactive UDF with 10,000 galaxies mapped. Wikisky.org]

References