The Lagoon Nebula was discovered by Guillaume Le Gentil in 1747 and is one of only two star-forming nebulae faintly visible to the naked eye from mid-northern latitudes. Seen with binoculars, it appears as a distinct oval cloud-like patch with a definite core. A fragile star cluster appears superimposed on it.
The Lagoon Nebula is estimated to be between 4,000-6,000 light years from the Earth. In the sky, it spans 90' by 40', translates to an actual dimension of 110 by 50 light years.
Like many nebulae, it appears pink in time-exposure color photos but views with the naked eye do not show any color either through binoculars or even large telescopes. This is because human vision has poor color sensitivity at low light levels.
The nebula contains a number of Bok globules (dark, collapsing clouds of protostellar material), the most prominent of which have been catalogued by E. E. Barnard as B88, B89 and B296. It also includes a funnel-like or tornado-like structure caused by a hot O-type star that emanates ultraviolet light, heating and ionizing gases on the surface of the nebula. The Lagoon Nebula also contains at its centre a structure known as the Hourglass Nebula (so named by John Herschel), which should not be confused with the better known Hourglass Nebula in the constellation of Musca. In 2006 the first four Herbig-Haro objects were detected within the Hourglass, also including HH 870. This provides the first direct evidence of active star formation by accretion within it.
sagittarius.jpgTo find the Lagoon Nebula first locate the star Nunki which represents the Archer's right shoulder. Next locate Kaus Borealis and draw a line from Nunki to Kaus Borealis. Continue your line through Kaus Borealis and onwards about the same distance as that between Nunki and Kaus Borealis. You should have arrived at the Lagoon Nebula (M8 on the attached map).