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M42, The
Great Orion Nebula
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This region is in the constellation Orion in the lower
end of his sword. M42, the primary nebula, is about 1,600 light years
distant. It is a diffuse nebula with characteristics of both emission
and reflection nebulosity and is a region of active star birth. The
gas and dust clouds visible in this image are a very small part of a much
larger cloud called Orion B that extends up to Orion's belt and well beyond.
In addition to M42, M43, de Marian's Nebula is visible here as the upside
down comma shaped region above the main nebula. The main nebula is the
second "star" up from the tip of Orion's sword.
Above that is the open cluster NGC 1977. In long
exposure photography this open cluster displays reflection nebulosity and is
commonly called "The Running Man" for the distinct dark dust lanes present
in the nebulosity. This is the third "star" up from the tip of the
sword.
The bright star below the main nebula is Nair Al Saif and
is itself, along with the gas and dust around it, classified as the diffuse
nebula, NGC 1980. This 2.75 magnitude blue giant star is 24 times
larger than our sun and a double star. It is the tip of Orion's sword.
Two versions of the main nebula are shown here. The
top right version shows the relative brightness of the various parts of the
main nebula. The core is centered around the Trapezium, a cluster of
four massive, very hot and young stars born from this cloud of dust and gas
along with two smaller companions. The Trapezium is the source of
energy for the emission nebulosity of this object. The region around
the Trapezium is much brighter than the outlying shells of gas which makes
M42 the best of nebula targets for visual observers.
The left, full frame image is a masked image using
Photoshop to show the inner details of the core region. Click
Here
for the techniques used to mask this image. Two masks of the core
region were used. Each is shown below the upper right image and each
was used to mask the burned out core of the original image in succession.
The larger mask on the left was used to mask the original image to bring out
the outer core, and the smaller on the right masked the larger mask to bring
out the details of the inner core. The second mask is the same image
as the first mask with a levels reduction to avoid burning out the Trapezium
region.
After masking additional processing using curves and
levels layers was done to enhance the contrast.
Back to Messier Gallery
Date: 10/7/2005
Location:
Okie-Tex Star Party,
Kenton, OK
Telescope: Orion 80ED @ f/7.5
Camera: Canon 20D,
ISO 800
Exposure Count: 18 frames @ 3 minutes, total
exposure 54 minutes
Core Masks: 3 frames @ 20 seconds, 5 frames at 10 seconds
using Hutech Type I 350D, 1/28/06, American Horse Lake.
Guiding: Unguided
Acquisition and Focus: DSLR Focus
Post Processing: Images Plus, Photoshop, Neat Image
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