The northern sky contains the faint yet recognisable constellation Sagitta. Not to be confused with the much larger constellation Sagittarius, known as "the archer," its name is Latin for "arrow." It was one of the forty-eight constellations listed by the astronomer Claudius Ptolemy in the second century, and it is still one of the eighty-eight constellations recognised by the International Astronomical Union today. Sagitta is one of the oldest constellations, yet while having no stars brighter than the third magnitude, it has the third-smallest area of any constellation.
With an apparent magnitude of 3.47, Gamma Sagittae is the brightest star in the constellation. It is an old red giant star that is fifty-four times larger in diameter than the Sun and is 90 percent as massive. Small telescopes may reveal the individual stars that makeup Delta, Epsilon, Zeta, and Theta Sagittae. A white dwarf accreting mass from a donor star makes up the binary star system known as V Sagittae, a cataclysmic variable that is predicted to become nova and temporarily become the most brilliant star in the Milky Way and one of the brightest stars in our sky around the year 2083. It is known that two-star systems in Sagitta contain planets like Jupiter, while a third, 15 Sagittae, contains a brown dwarf companion. |
History
One of the forty-eight constellations listed by Claudius Ptolemy, Sagitta Oistos was known to the ancient Greeks as "the arrow" (kunitzsch 2002). It was said to be the tool Hercules used to dispatch the eagle of Jupiter (Aquila) that was constantly gnawing on Prometheus' liver. Beyond Aquila, the Eagle's northern boundary is where Sagitta is situated. Richard Hinckley Allen, an amateur naturalist, proposed that the constellation might be a representation of the arrow that Hercules fired at the nearby Stymphalian birds (which appear in Hercules' sixth labour) that were symbolised in the sky by the constellations Aquila the Eagle, Cygnus "The Swan," and Lyra "The Vulture," and still lying between them, thus the name Herculea. These birds had iron claws, beaks, and wings (Allen 1963) It was identified by the Greek scholar Eratosthenes as the arrow that Apollo used to kill the Cyclopes. Romans gave it the name Sagitta. (Bagnall 2012) Although this name changed to Sham and was solely applied to the constellation Alpha Sagittae, it became al-SAHM, or "arrow," in Arabic. The Greek word has also been incorrectly translated into Arabic as "al-nawl" and istos, which means "the loom." It was also known as al-'anaza, which means "pike/javelin." (Kunitzsch 2002) |
Characteristics
An asterism in the shape of an arrow is composed of the four brightest stars and is situated directly north of the star Altair. (Moore 2005) With an extent of 79.9 square degrees or 0.194 percent of the sky, Sagitta is the 86th-largest among the eighty-eight contemporary constellations. Only Crux and Equuleus are smaller. Northern hemisphere astronomers can most easily observe Sagitta from late spring to early autumn, with its midnight culmination falling on July 17. (Thompson & Fritchman 2007) Because of its location in the Northern Celestial Hemisphere, observers north of 69°S may see the entire constellation. Sagitta is bordered to the north by Vulpecula, to the west by Hercules, to the south by Aquila, and to the east by Delphinus.
The International Astronomical Union adopted the three-letter abbreviation "Sge" for the constellation in 1922. American astronomer Henry Norris Russell produced the code but had to use the genitive form of the name to find a letter to include ('I) that was not in the name of the constellation Sagittarius. (Russell 1922) A polygon with twelve parts, established by Belgian astronomer Eugène Delporte in 1930, serves as the official constellation limits. These borders' right ascension values in the equatorial coordinate system range from 18h 57.2m to 20h 20.5m, while their declination coordinates range from 16.08° to 21.64°.
An asterism in the shape of an arrow is composed of the four brightest stars and is situated directly north of the star Altair. (Moore 2005) With an extent of 79.9 square degrees or 0.194 percent of the sky, Sagitta is the 86th-largest among the eighty-eight contemporary constellations. Only Crux and Equuleus are smaller. Northern hemisphere astronomers can most easily observe Sagitta from late spring to early autumn, with its midnight culmination falling on July 17. (Thompson & Fritchman 2007) Because of its location in the Northern Celestial Hemisphere, observers north of 69°S may see the entire constellation. Sagitta is bordered to the north by Vulpecula, to the west by Hercules, to the south by Aquila, and to the east by Delphinus.
The International Astronomical Union adopted the three-letter abbreviation "Sge" for the constellation in 1922. American astronomer Henry Norris Russell produced the code but had to use the genitive form of the name to find a letter to include ('I) that was not in the name of the constellation Sagittarius. (Russell 1922) A polygon with twelve parts, established by Belgian astronomer Eugène Delporte in 1930, serves as the official constellation limits. These borders' right ascension values in the equatorial coordinate system range from 18h 57.2m to 20h 20.5m, while their declination coordinates range from 16.08° to 21.64°.
Deep-sky Objects
Main stars - 4
Bayer stars - 19
Stars with planets - 2
Stars brighter than Magnitude 3.00 - 0
Stars within 32 Ly - 2
Messier objects - 1
Bordering
constellations
- Messier 71 (M71) – Globular Cluster
- NGC 6886 – Planetary Nebula
Main stars - 4
Bayer stars - 19
Stars with planets - 2
Stars brighter than Magnitude 3.00 - 0
Stars within 32 Ly - 2
Messier objects - 1
Bordering
constellations
- Vulpecula
- Hercules
- Aquila
- Delphinus