NGC 3372, the Eta Carinae Nebula, is one of the largest and brightest emission nebula complexes in the sky. It is located in Carina in the southern hemisphere. Although it is 5 times farther away, it is larger in apparent size than M42, the Great Nebula in Orion.

The nebula is a giant complex of emission and dark nebulae surrounding the unique variable star Eta Carinae, which scientists believe is the most massive and energetic star in the Milky Way Galaxy.

The dark three-pronged wedge inside the bright nebula is a dark nebula called the Keyhole nebula and is listed as NGC 3342.

Located approximately 7,500 to 10,000 light-years from the Earth, the nebula spans more than 300 light-years in space and is one of the largest star-forming regions in the Milky Way Galaxy.

Eta Carinae, the star, is more than 100 times as massive as our own Sun, and produces 4 million times the light output. The brightness of Eta Carinae varies wildly and seemingly erratically. In the 1840's, it brightened to the point where it was the second brightest star in the sky, and in 1868 faded to the point where it was not visible. This behavior is not fully understood.

Astronomers believe that the massive Eta Carinae has lived perhaps one million years and that it may survive for another couple of hundred thousand years or less before it explodes in a supernova.

The Eta Carinae nebula was discovered by Abbé Nicolas Louis de Lacaille in 1751.

North is to the right in the above image.

Photo by Jerry Lodriguss and John Martinez.

NGC 3372 Catalogs: NGC 3372, Gum 33 Common Name: Eta Carinae Nebula Object Type: Emission Nebula Complex Magnitude: 3.0b Size: 3° x 2° Constellation: Carina Image Field Centered At: RA: 10h 46m 00s Dec: -59° 47' 40"