M16 - Eagle Nebula (H-alpha)
M16 - Eagle Nebula (H-alpha): The Eagle Nebula, which includes the "Pillars of Creation" are imaged here in H-alpha, a "red" emission line (656nm) of Hydrogen. 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 hydrogen 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: June 2010
Telescope: Meade 16" Schmidt Cassegrain
Camera: SBIG ST-10XE
3nm Astrodon H-alpha filter
Exposure: 9x10 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 of L into Photoshop. Adjusted curves and levels. Slight blur on the dim areas and sharpening on non-star bright areas.
Links to images of this object on other sites:
Additional Comments: This is the "first light" 3nm H-alpha image at the Fort Lewis observatory. The previous 6nm first light image is found here: http://www.fortlewis.edu/observatory/image_detail.asp?ID=84
Numerous other Eagle Nebula images can be found by searching this site for M16.
When excited electrons in a hydrogen atom decay from a higher excited state into the first excited state, the photons emitted are part of the Balmer series. The lowest energy transition in this series is going from the second to the first excited state, in which case a red, H-alpha (656.3nm) photon is emitted. Going directly from the third excited state to the first excited state, the atom will emit an H-beta photon (486.1nm). When an electron decays to the ground state, which is a much larger energy drop, an ultraviolet photon is emitted. For more information, see: http://en.wikipedia.org/wiki/Balmer_series