CHAMÄLEON + ONJALA OBSERVATORY DeepSky SITEMAP
HOME CHAMÄLEON
 
« back to overview Nebulae  
The image processing of narrow band recordings differs fundamentally from the classical processing of RGB or LRGB recordings. This is due to the fact that specific emission lines are "captured" in narrow-band images, which have to be separated from the eye in their later visual representation. However, this is not always easy, since for example the emission line of sulphur-II is very close to that of hydrogen-alpha and nitrogen-II. These lines are all red for the human eye. The emission lines of hydrogen-beta and oxygen-III, however, are both located in blue (or turquoise) for the human eye. In order to enable the viewer to separate the information in the processed image, one tries to assign the emission lines to a "false color" corresponding to the general color theory (keyword: complementary colors).
 
Narrow band images of NGC 3603 and 3576, IC 2944/48 and NGC 6188 and 6193
 
NGC 3603 und 3576
H-SHO
IC 2944/48
H-SHO
NGC 6188 und 6193
H-SHO
With these three images we welcome Bernd Gooßmann as 4th member of the Team Chamäleon. He writes to the images ...
  • HOO: The red channel is assigned to the hydrogen alpha signal, the green and blue channel to the oxygen III signal. This results in a coloration that comes very close to the original object colors of the gas nebula.
  • SHO: This is the classic Hubble palette. The red channel is assigned to the sulfur II signal, the green channel to the hydrogen alpha signal and the blue channel to the oxygen III signal. Since the image initially appears predominantly greenish, the intensity of the green channel is significantly reduced during image processing, resulting in a very harmonious color distribution that the human eye can differentiate very well. Unfortunately, with this procedure all stars are shifted into a pink hue, which looks not very good. However, this can be corrected with a few processing steps.
  • H-SHO: The procedure is the same as for SHO, but the resulting image only serves as chrominance information. The luminance is represented by the hydrogen alpha signal which often includes the most details due to its overwhelming proportion in the gas nebula. If the SHO chrominance signal is modulated with the image of the hydrogen alpha, the result is an extremely sharp and detailed image, which contains the color distribution of the Hubble palette and is "conclusive" for the human eye.
Load higher resolution (1800 x 1350 Pixel)   (2400 x 1800 Pixel)
Image data - Exposure: 18x180s H-alpha, je 16x180s SII,OIII, Filter: Astrodon 3nm, Camara: ASI 1600-MMpro, Telescope: 6" Zeiss APQ - f/8
An object description about NGC 3603 und NGC 3576 can be found here ...
 
Load higher resolution (1800 x 1350 Pixel)   (2400 x 1800 Pixel)
Image data - Exposure: 17x220s H-alpha, je 14x220s SII,OIII, Filter: Astrodon 3nm, Camara: ASI 1600-MMpro, Telescope:: 105mm Pentax - f/6
An object description about IC 2944 und IC 2948 can be found here ...
 
Load higher resolution (1400 x 1900 Pixel)
Image data - Exposure: 18x220s H-alpha, je 14x220s SII,OIII, Filter: Astrodon 3nm, Camara: ASI 1600-MMpro, Telescope:: 105mm Pentax - f/6
An object description about NGC 6193 und NGC 6188 can be found here ...

Sun Moon Solar System DeepSky Widefield Miscellaneous Spec. Projects

 
All Images and all Content are © by Franz Hofmann, Wolfgang Paech, Dirk Lucius und Bernd Gooßmann