M16 - Eagle Nebula ([SII])
M16 - Eagle Nebula ([SII]): The Eagle Nebula, which includes the "Pillars of Creation" are imaged here in [SII], a "forbidden" emission line (near 672 nm) of singly ionized Sulphur. In star forming regions, gravity pulls together clumps from the cloud of gas that collapse and form the stars. The first stars that form are the massive, bright blue stars near the center of the cluster. These emit lots of ultraviolet light that then excites the gas in the surrounding clouds. The intense radiation from these same stars is also "blowing away" the clouds - in direct competition with gravity. These competing forces give the "melting candle wax" appearance of parts of this nebula.
Right Ascension: 18h 18.8m
Declination: -13° 47'
Apparent Magnitude: 6.4
Date: August 2010
Telescope: Meade 16" Schmidt Cassegrain
Camera: SBIG ST-10XE
6nm Astrodon [SII] filter
Exposure: 11x10 minutes binned 2x2
The camera was at -35°C
Processing Notes: Data acquisition with CCDSoft. Reduced and aligned in CCDStack. Subs combined in Sigma Beta. Arcsine stretch import into Photoshop. Adjusted curves and levels. Slight blur on the dim areas and sharpening on non-star bright areas. A highpass filter of the non-star regions was overlayed to increase contrast. Slight minimum filter on the brighter stars.
Links to images of this object on other sites:
Additional Comments: The 2010 H-alpha image of M16 from the Fort Lewis observatory is found here: http://www.fortlewis.edu/observatory/image_detail.asp?ID=212
Numerous other Eagle Nebula images can be found by searching this site for M16.
Although H-alpha is the predominant line giving the red color to emission nebulae, [SII] is often mapped to red in narrow band images because it is very slightly redder (672 nm) than the Hydrogen line (656 nm).