Tuesday, September 28, 2010
A star suppression example
An animated image of the star and starless versions of the "Wizard Nebula"
I often use a starless image in one of the processing steps of the astronomical image.
Sometimes I publish the starless version too, it looks kind of nice, or spooky, that's a matter of taste.
If there is a dense star-field, nebula itself could be hard to detect. When stars are suppressed, the nebula can be seen better due the fact, that human brains tend to form false shapes from the cloud of dots.
Here is an example of my "Tone Mapping" technique:
A PDF-tutorial can be found behind this link:
M57, the "Ring Nebula", a new imaging project
M57, NGC 6822, the "Ring Nebula", locates in constellation Lyra and the distance is about 2300 light years.
Last night I started a new imaging project with the M57. I'm targeting to expose outer shells of this planetary nebula. There is two layers of outer shells, both very dim. In this image the first shell is visible clearly and there is a hint of the second one. There is now 2h 40min. of H-alpha exposures, least ten more hours is needed to show the structure in H-a light.
The, 1.2 solar masses, white dwarf in the center of the nebula has visual magnitude 15,75. It can't be seen in a H-alpha light image, it will be interesting to see, if it'll shows at O-III channel I'm gonna shoot later.
Too bad, that I'm not able to shoot any broad band luminance data due my intense light pollution, with H-a, needed exposure time will be very long..
Too bad, that I'm not able to shoot any broad band luminance data due my intense light pollution, with H-a, needed exposure time will be very long..
This target is not very high, here at 65N. Maximum elevation is about 50 degrees and after two and half hours, it was only about 30. Since this is a small target, good seeing and reasonable altitude is needed to show any details.
Technical details:
processing work flow:
Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack.
Levels and curves in PS CS3.
Telescope, Meade LX200 GPS 12" @ f5
Camera, QHY9 Guiding, SXV-AO @ 10Hz
Image Scale, 0,75 arcseconds/pixel
Exposures H-alpha 7x1200s, binned 1x1
Monday, September 27, 2010
Sh2-142, the "Wizard Nebula"
Sh2-142 alias NGC 7380, in HST-palette, (HST=Hubble Space Telescope)
from the emission of ionized elements, R=Sulfur, G=Hydrogen and B=Oxygen.
I use a starless image in one of the processing steps. Sometimes I publish it, since the actual nebula can be better seen by this way.
Natural color composition from the emission of ionized elements, R=80%Hydrogen+20%Sulfur, G=100%Oxygen and B=85%Oxygen+15%Hydrogen to compensate otherwise missing H-beta emission. This composition is very close to a visual spectrum.
NGC 7380 is a catalog number of the open star cluster inside Wizard nebula, SH2-142.
Nebula locates in constellation Cepheus, about 7000 light years from my home.
Technical details:
Processing work flow:
Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack.
Deconvolution with a CCDSharp, 30 iterations.
Levels, curves and color combine in PS CS3.
Telescope, Meade LX200 GPS 12" @ f5
Camera, QHY9 Guiding, SXV-AO @ 6,5Hz
Image Scale, 0,75 arcseconds/pixel
Exposures H-alpha 15x1200s, binned 1x1
S-II 1x1200s, binned 4x4
O-III 1x1200s, binned 4x4
I have used color data from an older, 2008, wide field image of Sh2-142.
Technical details for image used for colors:
Sunday, September 26, 2010
NGC 2070, the "Tarantula Nebula"
NGC 2070 in HST-palette, (HST=Hubble Space Telescope)
from the emission of ionized elements, R=Sulfur, G=Hydrogen and B=Oxygen.
This composition is very close to a visual spectrum.
Tarantula nebula, NGC 2070, also known as 30 Doradus, is an ionized Hydrogen region in the Large Magellanic cloud, visible in southern hemisphere. Distance from Earth is about 160.000 light years.
A closeup of Tarantula Nebula
The telescope and technical information:
16" RCOS ja Apogee U9000 camera.
LRGB combo.
H-alpha 5x1200s, Dark and artificial Flat calibrated.
2 x O-III 1200s and 5 x 900s Dark and artificial Flat calibrated.
2 x S-II 1200s, Dark and artificial Flat calibrated.
Raw data is shared with "Team Finland"
Processing workflow:
Image acquisition, MaxiDL v4.xxx
Stacked and calibrated in CCDStack.
Deconvolution with a CCDSharp, 30 iterations added 50% to non convoluted data
Levels, curves and color combine in PS CS3.
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