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Messier 78, NGC 2071 and NGC 2112 in the constellation of
Orion in a a wide angle view |
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Short object description
Our wide field image shows Messier 78 in the centre. It is a complex of
reflection nebulae embedded in the large dark cloud Barnard 33 (LDN 1624). The
object lies in the constellation Orion and is about 1600 light years away from
the solar system. M 78 was discovered by Pierre Mechain in March 1780. Our
image shows very nicely that the large molecular cloud Barnard 33 extends into
the area of NGC 2024 and IC 343.
While in emission nebulae gas clouds are stimulated to glow by
ionisation of energetic stars, in reflection nebulae the gas masses only
reflect the light of bright stars. Messier 78 is one of the brightest
reflection nebulae in the sky and can already be observed with smaller
telescopes in dark surroundings. |
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The
two bright stars HD 38563 A and
HD 38563 B produce a major part of the light that
illuminates the reflection nebulae. However, the nebula is home to many more
stars, including a collection of 45 low-mass, young stars, so-called T Tauri
stars, which are less than 10 million years old and are hidden behind the dust
clouds.
Our wide-angle image
shows, next to M78 on the left, a part of Barnard's
Loop, an extended, red glowing, H-II region. It lies about 1600
light-years from the solar system, about the same distance as Messier
78.
« Click here or the thumbnail to load a large annoted image
and a size comparison to the full moon.
A higher resolution image of M 78, taken with a longer
focal length,
is shown here. |
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Approximately at the same altitude as M78 (on the left) lies the open
star cluster NGC 2112, which is about 2800 light-years away from the H-II
region of Barnard's Loop. According to Trumpler, the star cluster is assigned
to class II 3 m. It was discovered by Friedrich Wilhelm Herschel on 1 January
1786.
The two bright stars on the
lower right of the image are Alnitak (left) and Alnila (with NGC 1990), are two
of the 3 belt stars of the constellation Orion. The nebula area to the left of
Alnitak is NGC 2024. NGC 2024 is a mixture of emission, reflection and dark
nebula and is also 1600 light years away. It was discovered on 1 January 1786
by Friedrich Wilhelm Herschel, the father of William Herschel.
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« The picture on the left
shows the core of Messier 78, taken with the MPG/ESO 2.2-meter telescope at the
La Silla Observatory in Chile. Credit:
https://commons.wikimedia.org/wiki/File:Messier_78.jpg
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All Images and all Content are © by Franz Hofmann
+ Wolfgang Paech |