M 8 - Laguna Nebula in Sagitarius

Messier 8 (NGC 6523 or Lagoon Nebula) is a giant interstellar cloud in the constellation Sagittarius. It was discovered by Giovanni Hodierna before 1654 and is one of only two star-forming nebulae faintly visible to the naked eye from mid-northern latitudes. The distance to the Lagoon Nebula is estimated to be between 4,000-6,000 light years. In the sky it spans 90' by 40', translates to an actual dimension of 110 by 50 light years. 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 structure caused by a hot O-type star that emanates ultraviolet light, heating and ionizing gases on the surface of the nebula. At its centre the Lagoon Nebula also contains 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. Much large image including M 8 can be found here .

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