Physics Photo of the Week
Orion Nebula - Discussion by Molly Herold
Photos by Brent Figlestahler and Donald Collins
of the Orion Nebula were taken from just outside Spidel on the evening
of December 3rd, 2008. The object was photographed with and with out an
H-alpha filter. Several pictures were taken at a 4 second time
exposure. The photos were then stacked the on top of one another to
reduce noise. The images were adjusted in terms of contrast and
brightness to enhance the view of the Nebulous cloud.
The Orion Nebula can be seen with the naked eye and is seen as a
smudged star just below Orion’s belt. The Nebula is made up of several
hot, bright young stars that are surrounded by a cloud of dust and gas.
The massive size of this object is actualized when you consider it is
several light years wide itself. The angular size of the complete
nebula is more then 4 times the area of the full moon. This deep sky
object is actually part of an even larger structure known as the Orion
Molecular Cloud Complex which includes the Horsehead Nebula, M34, the
Flame Nebula and Barnard’s Loop.
photographed with a color camera, the Nebula can be seen in an
astonishing array of Blue, Red and Green all caused by reflective
radiation of stars in the core. Using the H-alpha filter in this second
image we are allowed to see only a small band of emission from the
object - the hydrogen spectra. This is helpful because it allows us to
see the cloud of the Nebula with greater clarity, since it is made up
of about 90% hydrogen. The H-alpha filter suppresses the images
of the stars because the stars are mostly incandescent sources, whereas
the nebula has most of its light concentrated in the H-alpha color.
Watch for color images of the Orion Nebula to be made by students in
Earth, Light,and Sky.
[Note: Molly Herold and Brent Figlestahler both completed Contemporary
Astronomy in the fall 2008 semester.]
Photo of the
published weekly during the academic year on Fridays by the Warren
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