Explanation:
Alnitak,
Alnilam,
and
Mintaka,
are the bright bluish stars
from east to west (left to right) along the diagonal in
this gorgeous cosmic vista.
Otherwise known as the
Belt of Orion, these
three blue supergiant stars are hotter and much more
massive than the Sun.
They lie about 1,500 light-years away, born
of Orion's
well-studied interstellar clouds.
In fact, clouds of gas and dust adrift in this region have
intriguing and some surprisingly familiar shapes, including the
dark Horsehead
Nebula and Flame Nebula near
Alnitak at the lower left.
The famous Orion Nebula
itself lies off the bottom of
this star field that covers an impressive 4.4x3.5
degrees on the sky.
The color picture was composited from
digitized
black and white photographic plates recorded
through red and blue astronomical filters, with a computer synthesized
green channel.
The plates were taken using the
Samuel
Oschin Telescope, a wide-field survey instrument at
Palomar
Observatory, between 1987 and 1991.
