Tuesday, February 26, 2013
The Veil Nebula, an experimental 3D-study
This is an experimental test with a 3D-conversion of my astronomical images. Only real elements from my image are used, there is nothing added but the volumetric information!
(In this image, some of the stars are enhanced for a visual reasons)
NOTE. This is a personal vision about shapes and volumes, based on some scientific data and an artistic impression.
Veil Nebula supernova remnant as a 3D-model
In constellation Cygnus, animation in natural colors
This is a looped video, click to start and stop. Original movie is in HD1080p resolution.
An other version of the animated Veil
Animation in mapped colors
This is a looped video, click to start and stop. Original movie is in HD1080p resolution.
My original image of the Veil Nebula is used for the animations
Click for the large image
Blog post about this image with technical details:
http://astroanarchy.blogspot.fi/2012/03/veil-nebula-reprocessed-with-some-new.html
An animated GIF
Click for a large image
Blog post about the animated GIF can be seen here:
http://astroanarchy.blogspot.fi/2012/10/an-experiental-3d-animation-from-my.html
My original image of the Veil Nebula is used for the animations
Click for the large image
As can be seen here, the compression in YouTube has lost some details from above videos, they are all in original, less compressed, video.
Blog post about this image with technical details:
http://astroanarchy.blogspot.fi/2012/03/veil-nebula-reprocessed-with-some-new.html
An animated GIF
Blog post about the animated GIF can be seen here:
http://astroanarchy.blogspot.fi/2012/10/an-experiental-3d-animation-from-my.html
HOW IT'S DONE
For as long as I have captured images of celestial objects, I have always seen
them three-dimensionally in my head. Over time I realized that we actually have
enough scientific information to build a coarse skeleton model of the nebula itself.
The scientific information makes my visions much more accurate, and the 3-D technique I have developed enables me to share those beautiful visions with others.
How accurate my 3-D-visions are depends on how much accurate information I have and how well I implement it. Also, many different estimates are
needed for the 3-D model. The final 3-D-image is always an appraised simulation
of reality based on known scientific facts, deduction, and some artistic creativity
on top of everything else
After I have collected all the necessary scientific information about my target,
I start my 3-D conversion using the stars in the image. Usually there is a recognizable star cluster which is responsible for ionizing the nebula. We don’t need to
know its absolute location since we know its relative location. Stars ionizing the
nebula have to be very close to the nebula structure itself. I usually divide up the
rest of the stars by their apparent brightness, which can then be used as an indicator of their distances, brighter being closer. If true star distances are available
I use them, but most of the time my rule of thumb is sufficient.
By using a scientific estimate of the distance of the Milky Way object, I can
then locate the correct number of stars in front of it and behind it.
Emission nebulae are not lit up directly by starlight; they are usually way too
large for that. Rather, stellar radiation ionizes elements within the gas cloud. So it
is the nebula itself that is glowing, at the characteristic wavelengths of each ionized element. (The principle is very much the same as in fluorescent tubes.) I use
this information for my 3-D model. The thickness of the nebula can be estimated
from its brightness, since the whole volume of gas is glowing, brighter means
thicker. By this means, forms of the nebula can be turned to a real 3-D shape.
Nebulae are also more or less transparent, so we can see both sides of it at the
same time, and this makes model-making a little easier since not much is hidden.
The local stellar wind, from the star cluster inside the nebula, shapes the
nebula by blowing away the gas around the star cluster. The stellar wind usually
forms a kind of cavity in the nebulosity. The same stellar wind also initiates the
further collapse of the gas cloud and the birth of the second generation of stars
in the nebula. The collapsing gas can resist the stellar wind and produces pillarlike formations which must point to a cluster.
Ionized oxygen (O-III) glows with a bluish light, and since oxygen needs a lot
of energy to ionize it, this can only be achieved relatively close to the star cluster
in the nebula. I use this information to position the O-III area (the bluish glow) at
the correct distance relative to the heart of the nebula.
Many other small indicators can be found by carefully studying the image
itself. For example, if there is a dark nebula in the image, it must be located in
front of the emission nebula, otherwise we can’t see it.
Using the known data in this way I build a kind of skeleton model of the
nebula. Then the artistic part is mixed with the scientific and logical elements,
and after that the rest is very much like creating a sculpture on a cosmic scale
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