Sunday, March 8, 2015
IC 417, the "Spider Nebula"
My latest photo from March 6, IC 417, an emission nebula in Auriga.
IC 417
Click for a large photo
Image is in mapped colors from an emission of the ionized elements. Golden areas
are from emission of sulfur and hydrogen, bluish hues are from ionized oxygen.
A closeup
Click for a large photo
INFO
Image in visual spectrum
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.
An experimental starless image
There is an interesting looking round formation at one o'clock position upper right.
Looks like a crater in a gas. It doesn't seem to be a planetary nebula since there is no O-III emission visible.
Image in H-alpha light alone
IC 417
Click for a large photo
are from emission of sulfur and hydrogen, bluish hues are from ionized oxygen.
A closeup
Click for a large photo
INFO
The cosmic spyder, IC 417, locates in constellation Auriga at a distance of about 10 000 light years.
A cluster of young stars around IC 417 makes elements in the gas glow and the stellar wind shapes the gas in various forms.
Image in visual spectrum
An experimental starless image
Looks like a crater in a gas. It doesn't seem to be a planetary nebula since there is no O-III emission visible.
Image in H-alpha light alone
Orientation in an older wide field photo
Technical details
Processing work flow
Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack2.
Deconvolution with a CCDStack2 Positive Constraint, 33 iterations, added at 50% weight
Color combine in PS CS3
Levels and curves in PS CS3.
Imaging optics
Celestron Edge HD 1100 @ f7 with 0,7 focal reducer for Edge HD 1100 telescope
Cameras and filters
Imaging camera Apogee Alta U16 and Apogee seven slot filter wheel
Guider camera, Lodestar x2
Astrodon filter, 5nm H-alpha
Astrodon filter, 3nm O-III
Astrodon filter, 3nm S-II
Exposure times
H-alpha, 12 x 1200s = 4h
O-III, 4 x 1200s = 1h 20 min.
S-II, 5x1200s = 1h 40 min.
Total 7h
A single un cropped, calibrated and stretched 20 min. H-alpha frame as it comes from the camera
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