Horsehead Nebula (B33)
The Horsehead Nebula (B33), also known as Barnard 33, is a dark nebula in the constellation Orion that projects into
the bright nebula IC 434 south of the star Alnitak (Zeta Orionis) in Orion's
Belt. It can only be seen well on long-exposure photographs and is often
used by amateur astronomers as a test of their observing skill. Its unusual
shape was first discovered on a photographic plate in the late 1800s. The
Horsehead is similar in form and nature to the famous pillars of dust and
gas known as the Eagle Nebula –
both are tower-like cocoons of young stars.
||6' × 4'
||1,600 light-years (490 pc)
||R.A. 05h 40m 59s,
Dec. -02° 27' 30"
The Horsehead Nebula was the clear winner among more than 5,000 Internet
voters, who were asked in 2000 to select an astronomical target for the
Hubble Space Telescope to observe. The image (below) subsequently acquired
by Hubble shows a region of the nebula measuring 2.2 light-years (0.67 pc)
across in the horizontal dimension.
|Horsehead Nebula imaged by Hubble
AND STAR CLUSTERS