Click on image to enlarge
[SII] = Red, Halpha = Green, [OIII] = Blue
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[Sulfur II] only
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Hydrogen Alpha only
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[Oxygen III] only
Click on comparison image to enlarge
comparison of Emission line filter image versus HaRGB image*
* HaRGB image used courtesy of Rick Krejci
(this comparison shows how emission line imaging blocks the broadband synchrotron emission from the Crab's pulsar)
Finally, here is an animation of the Crab
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Emission line images taken December 26-27, 2003 from my backyard in Castro Valley, Ca.
C14 imaging scope @4430mm focal length (f/12.46) with Camera Rotator and stabilized with mirror locks
FLI IMG1024S imaging camera @ -40C
SBIG AO7 Adaptive Optics System
SBIG ST7E Guide/AO control camera @-20C
RCOS Dichroic Beam Splitter for AO7/IMG compatibility
FLI CFW 1 filter wheel
Custom Scientific Narrowband Emission Line Filter
[Sulfur II] 672.4nm 3nm FWHM
Hydrogen alpha 656.3nm 3nm FWHM
[Oxygen III] 500.7nm 3nm FWHM
Exposure details:
3 exposures of 45 minutes each for [SII], Halpha, [OIII] filters
6 hours 45 minutes total exposure time
Maxim DL used for IMG1024S control
CCDSOFT 5.00.71 used for AO7/ST7E control
Sigma prebeta 11 used for darks, flats, biases and light combine
Photoshop CS used for final touch up