Astro Anarchy

Monday, March 11, 2013

Rosette Nebula, a closeup

The weather up here 65N hasn't been very cooperative. My latest image, the Rosette Nebula, has taken during four different nights, about an hour at the time, before the clouds rolled in. Images are shot at 20.02, 25.02, 07.03 and 08.03. 2013.

I shot just H-alpha channel, other two channels, S-II and O-III are from an older wide field image of the same target.

"Rosette Nebula"

Ra 06^h 33^m 45^s Dec +04° 59′ 54″

Image is in mapped colors from the emission of ionized elements, R=Sulfur, G=Hydrogen and B=Oxygen.

INFO

The Rosette Nebula (also known as Caldwell 49) is a large, circular H II region located near one end of a giant molecular cloud in the Monoceros. The open cluster NGC 2244(Caldwell 50) is closely associated with the nebulosity, the stars of the cluster having been formed from the nebula's matter. The cluster and nebula locates at a distance of about 5,200 light years from Earth. The diameter is about 130 light years.

The radiation from the young stars ionized the atoms in the nebula, causing them to emit light, typical to each element, producing the visible nebula. Stellar winds, radiation pressure, from a group of stars cause compression to the interstellar clouds, followed by star formation in the nebula. This star formation is currently still ongoing.

Natural colors

from narrowband channels

Image is in visual spectrum and dominated by the red light emitted by ionized Hydrogen, H-alpha. Blueish hues are from ionized Oxygen, O-III.

A wide field image

A wide field image of the Rosette Nebula in visual colors, taken with the Tokina AT-X 300mm f2.8 camera lens and the cooled astronomical camera, QHY9.

Blog post about the image with technical data:

http://astroanarchy.blogspot.fi/2012/12/caldwell-49-rosette-nebula-reprocessed.html

A study about an apparent scale

Click for a large image!

Note. A moon size circle in the images as a scale. (Moon has an apparent size of 0.5 degrees, that's equal to 30 arc minutes)

Technical details

Processing work flow:

Image acquisition, MaxiDL v5.07.

Stacked and calibrated in CCDStack2.

Levels, curves and color combine in PS CS3.

Optics, Meade LX200 GPS 12" @ f5

Camera, QHY9

Guiding, SXV-AO, an active optics unit, and Lodestar guide camera 11Hz

Image Scale, ~0,8 arc-seconds/pixel

13 x 1200s exposures for the H-alpha, emission of ionized Hydrogen = 4h 20min.

Colors are taken from my older wide field image

A single unprocessed 1200 second frame of H-a emission

A single 20 min. frame, just calibrated and nonlinear stretched to visible.

Imaged with the QHY9 camera, Baader 7nm H-alpha filter and Meade LX200 12" telescope.

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

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

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

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

Saturday, February 23, 2013

3D-study of the Bubble Nebula

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.

The Bubble Nebula as a 3D-model

This is a looped video, click to start and stop. Original movie is in HD1080p resolution.

A different Bubble Nebula animation in visual colors

This is a looped video, click to start and stop. Original movie is in HD1080p resolution.

Original 2D-image used for the animation

The animated image is in mapped color palette, this one is in natural colors.

A blog post with technical details can be seen here:

http://astroanarchy.blogspot.fi/2011/03/bubble-nebula-reprocessed.html

Info about the technique used

Due to huge distances, real parallax can't be imaged in most of the astronomical objects.

I have developed an experimental technique to convert my astropics to a artificial volumetric models.

My 3-D experiments are a mixture of science and an artistic impression. I collect distance and other information before I do my 3-D conversion. Usually there are known stars, coursing the ionization, so I can place them at right relative distance. If I know a distance to the nebula, I can fine tune distances of the stars so, that right amount of stars are front and behind of the object.

I use a “rule of thumb” method for stars: brighter is closer, but if a real distance is known, I'm using that. Many 3-D shapes can be figured out just by looking carefully the structures in nebula, such as dark nebulae must be at front of the emission nebulae in order to show up etc...

The general structure of many star forming regions is very same, there is a group of young stars, as an open cluster inside of the nebula. The stellar wind from the stars is then blowing the gas away around the cluster and forming a kind of cavitation – or a hole — around it. The pillar-like formations in the nebula must point to a source of stellar wind, for the same reason.

How accurate the final model is, depends how much I have known and guessed right. The motivation to make those 3-D-studies is just to show, that objects in the images are not like paintings on the canvas but really three dimensional objects floating in the three dimensional space. This generally adds a new dimension to my hobby as an astronomical imager.

A screen shot of the 3D-model