M42, The Orion Nebula
| M42, imaged with a TAK 106ED equipped with a ST10XME camera and a hydrogen-alpha filter. Click on the image twice for full size. |
| H-alpha image from 10 x 5 minute exposures; TAK 106ED f/5 scope; ST10XME camera; external guiding Borg 77ED |
The Orion Nebula (M42, NGC 1976) is the brightest starforming emission nebula in the sky. It is
visible to the naked eye under moderately good conditions and is an interesting target with
telescopes of any size. It is relatively easy to find the Orion Nebula, as it surrounds the Theta
Orionis multiple star seen in the middle of the sword of Orion. The nebula is located at a distance
of about 1,500 light-years. It is very large and extends to over 1 degree in diameter, thus
covering more than four times the area of the Full Moon. Its diameter is about 40 light-years.
On the right side of the hydrogen-alpha image shown below is the nebula M43 (The Running Man
Nebula) which is also an emission nebula. Actually, the Orion Nebula is the most conspicuous
part of a much larger cloud of gas and dust which extends over 10 degrees or well over half of the
constellation Orion. It covers several hundreds of light-years.
More information on the Orion Nebula can be found in the following web sources:
http://en.wikipedia.org/wiki/Orion_Nebula
http://www.messier.obspm.fr/m/m042.html#odell2003
Because of its brightness, M42 is relatively easy to image if one is only interested in part of the
nebula. The problem in producing an image of the entire nebula is its great dynamic range. If the
dim outer areas are captured, the bright inner areas are overexposed. The hydrogen-alpha
images shown below is derived from five different exposures.....20 x 300 sec; 20 x 60 sec; 25 x 15
sec; 20 x 1 sec; and 40 x 0.5 sec. The different exposures were aligned and blended using
Photoshop.
visible to the naked eye under moderately good conditions and is an interesting target with
telescopes of any size. It is relatively easy to find the Orion Nebula, as it surrounds the Theta
Orionis multiple star seen in the middle of the sword of Orion. The nebula is located at a distance
of about 1,500 light-years. It is very large and extends to over 1 degree in diameter, thus
covering more than four times the area of the Full Moon. Its diameter is about 40 light-years.
On the right side of the hydrogen-alpha image shown below is the nebula M43 (The Running Man
Nebula) which is also an emission nebula. Actually, the Orion Nebula is the most conspicuous
part of a much larger cloud of gas and dust which extends over 10 degrees or well over half of the
constellation Orion. It covers several hundreds of light-years.
More information on the Orion Nebula can be found in the following web sources:
http://en.wikipedia.org/wiki/Orion_Nebula
http://www.messier.obspm.fr/m/m042.html#odell2003
Because of its brightness, M42 is relatively easy to image if one is only interested in part of the
nebula. The problem in producing an image of the entire nebula is its great dynamic range. If the
dim outer areas are captured, the bright inner areas are overexposed. The hydrogen-alpha
images shown below is derived from five different exposures.....20 x 300 sec; 20 x 60 sec; 25 x 15
sec; 20 x 1 sec; and 40 x 0.5 sec. The different exposures were aligned and blended using
Photoshop.