M16, the Eagle Nebula
Date: 12-14 September, 2015
Telescope: PlaneWave 12.5" CDK
Camera: FLI Proline16803
Exposure: 6 hours through Astronomik Ha (hydrogen alpha), OIII (doubly ionised oxygen) and SII (singly ionised silicon) filter set
FOV: 49' x 49'
Processed in PixInsight
This image uses the standard false colour Hubble Palette:
SII -> R
Ha -> G
M16, known as the Eagle Nebula is part of a diffuse emission nebula, or H II region. This region of active current star formation is about 7000 light-years distant. The spire of gas that can be seen coming off the nebula in the northeastern part is approximately 9.5 light-years or about 90 trillion kilometers long.
The brightest star in the nebula (HD 168076) has an apparent magnitude of +8.24, easily visible with good binoculars. It is actually a binary star formed of an O3.5V star plus an O7.5V companion.
The cluster associated with the nebula has approximately 460 stars, the brightest of spectral class O, a mass of roughly 80 solar masses, and a luminosity up to 1 million times that of the Sun. Its age has been estimated to be 1–2 million years.