Milwaukee Astronomical Society


M17 - NGC 6618 - The Swan Nebula


Messier 17 (M17) is an emission nebula with many names - the Swan Nebula, Omega Nebula, Checkmark Nebula, Horseshoe Nebula and Lobster Nebula. It is located in the Milky Way region near the constellation Scutum, but actually belongs to the constellation Sagittarius. This nebula is one of the brightest and largest star-forming regions of our Galaxy. M17 contains a 35 star Open Cluster named NGC 6618, however the entire nebula actually contains an estimated 800 stars. The nebula's red and pink colors are due to glowing hydrogen gas. M17 is located about 5,500 light years away and is 15 light years in diameter. It was discovered by Philippe Loys de Chéseaux in 1745.

Location Data
Constellation: Sagittarius
Right ascension: 18h 20.8m
Declination: -16° 11′
Distance:  5,500 ly
Size:  15 ly

Observation Data
Apparent magnitude: 6.0
Apparent size: 11.0' arcmins

The images With Blue Borders were taken using equipment provided by the MAS Observatory
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