Friday, February 25, 2011
Sh2-216, project finalized
Sh2-216, A planetary Nebula in Perseus, the closest PN to Earth ever discovered
Ra 04h 45m 35s Dec +46° 48′ 30"
Image is in HST-palette, (HST=Hubble Space Telescope) from the emission of ionized elements, R=Sulfur, G=Hydrogen and B=Oxygen. Star colors are mixed from the NB channels, Red=H-a, G=O-III and B= 85%O-III + 15%H-a. Total exposure time 17h
In this image, three emission lines are shown. Ionized Hydrohen (H-a) as Green, ionized Sulfur (S-II) as Red and ionized Oxygen (O-III) as Blue.
S-II region seems to be more expanded than H-a region, O-II is mainly in upper part of the PN but there is some at Right, at between the hydrogen filaments. H-a seems to be little more expanded at the Left side of the nebula, much more dimmer, than a Right side though.
This must be one of the dimmest targets I ever have shot!
I never have seen this target as a three band emission color image before, as far as I know, this must be the first! Generally there is very few images of this to compare, please, let me know, if you have seen this before as a narrowband three color image.
( Actually I have shot this one before, together with a SNR Sh2-221 back in March 2009)
( Actually I have shot this one before, together with a SNR Sh2-221 back in March 2009)
Note! There is a size of the full Moon marked, as a Gray circle, at a upper Right corner
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.
All three channels, Ha, S-II & O-III, as an animation
All three channels, Ha, S-II & O-III, as an animation
As astronomical cameras are usually gray scale CCD's, colors are made by imaging each of them separately, trough a filter. Color channels, usually three of them, are then composed to a final color image.
In this animation, used channels are shown one by one.
Processing work flow:
Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack.
Levels, curves and color combine in PS CS3.
Equipments:
Tokina AT-X 300mm f2.8 @ f2.8
Platform and guiding, Meade LX200 GPS 12" @ f5
Camera, QHY9
Guider, Lodestar
Image Scale, 3,79 arc seconds/pixel
Exposures:
Baader H-alpha 7nm 30x1200s, binned 1x1
Baader O-III 8,5nm 17x600s, binned 2x2
Baader S-II 8nm 25x600s, binned 2x2
Total exposure time 17h
I have shot this target before, March 2009, with even wider field.
http://astroanarchy.blogspot.com/2011/01/two-ways-to-end-life-planetary-nebula.html
At this image Sh2-216 can be seen with its neighbor, Sh2-221, a Supernova remnant. .
http://astroanarchy.blogspot.com/2011/01/two-ways-to-end-life-planetary-nebula.html
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment