Tag Archives: Altair

Sagittarius (The archer)

Constellation SagittariusSagittarius, the archer, is a zodiacal constellation that is rather easily found because of its distinctive teapot asterism. It is one of the 48 constellations cataloged by the 2nd century astronomer Ptolemy. It is located on the ecliptic between Scorpius and Capricornus. It can also be found by starting at Altair (a Summer Triangle star) and tracing southward along Aquila’s long axis. As is situated on southern most point of the ecliptic, this constellation hangs low in the southern sky, reaching its highest nightfall ascension in August. The Sun’s arrival at the southernmost point of the ecliptic around December 21st marks Winter Solstice and the first day of Winter.

This constellation has the distinction of presenting the foreground stars in the direction of the dense center of the Milky Way galaxy, which is rich in Messier objects. As such, it is worth taking the time to scan this constellation with binoculars or a small telescope. Several well-known nebula can be found in Sagittarius to include the Lagoon Nebula (M8), the Horseshoe Nebula, the Omega Nebula (M17), the Trifid Nebula (M20), and the Small Sagittarius Star Cloud (M24). Other Messier objects include M18, M22, M23, M25, M28, M54, M55, M69, M70 and M75.
http://en.wikipedia.org/wiki/Sagittarius_(constellation)

IAU Sagittarius chart, Sky & Telescope magazine, June 5, 2011.
IAU Sagittarius chart, Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 5, 2011.

© James R. Johnson, 2014.
jim@jrjohnson.net

Aquila (The eagle)

Scutum, Aquila, CapricornusAquila is a  fairly easily recognized constellation of medium to bright stars that is one of the 48 constellations cataloged by 2nd century astronomer Ptolemy. It is a pretty constellation that easily evokes an image of a soaring eagle. Lying south of Cygnus, and flanked by Pegasus to the east and Ophiuchus to the west, Aquila reaches its highest nightfall ascension in September.

The most notable star in Aquila is Altair (Alpha Aquilae), its brightest star and a member of the Summer Triangle. Aquila lies in the same direction as the Milky Way, so several  gaseous nebula can be found in this constellation. The most famous of these are the Owl Nebula (NGC6781) and the Glowing Eye nebula (NGC6751),
http://en.wikipedia.org/wiki/Aquila_(constellation)

IAU Aquila chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 4, 2011.
IAU Aquila chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 4, 2011.

© James R. Johnson, 2014.
jim@jrjohnson.net