M1 Crab Nebula in [SII], [NII] and Ha Light

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[SII] = Red, [NII] = Green, Halpha = Blue

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[Sulfur II] only

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Hydrogen Alpha only

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[Nitrogen II] only

All these emission lines (Sulfur, Nitrogen and Hydrogen) are contained within the Red portion of the spectrum. This image separates the three spectral lines and assigns them to RGB colors to better reveal structure normally confined to the red portion of the spectrum.

Taken December 25-26, 2003 from my backyard in Castro Valley, Ca.

C14 imaging scope @4430mm focal length (f/12.46) stabilized with mirror locks and with camera angle adjuster

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

   [Nitrogen II]                658.3nm  3nm FWHM

   Hydrogen alpha        656.3nm  3nm FWHM 

Exposure details:

3 exposures of 45 minutes for [SII], [NII], Halpha

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

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