Lyra (Constellation)

Lyra , Latin for lyre, from Greek λύρα) is a small constellation. It is one of 48 listed by the 2nd century astronomer Ptolemy, and is one of the 88 constellations recognized by the International Astronomical Union. Its principal star, Vega (Abhijit in Sanskrit), a corner of the Summer Triangle, is one of the brightest stars in the sky. Beginning at the north, Lyra is bordered by Draco, Hercules, Vulpecula, and Cygnus. Lyra is visible from the northern hemisphere from spring through autumn, and nearly overhead, in temperate latitudes, during the summer months. From the southern hemisphere, it is visible low in the northern sky during the winter months.

Messier 57 also known as the "Ring Nebula" and NGC 6720, has a diameter of one light-year and is at a distance of 2,000 light-years from Earth. It is one of the best known planetary nebulae and the second to be discovered; its integrated magnitude is 8.8. It was discovered in 1779 by Antoine Darquier, 15 years after Charles Messier discovered the Dumbbell Nebula. Astronomers have determined that it is between 6,000 and 8,000 years old; it is approximately one light-year in diameter.The outer part of the nebula appears red in photographs because of emission from ionized hydrogen. The middle region is colored green; doubly-ionized oxygen emits greenish-blue light.

References

Found in HGS Manual on Page 108

Found in HGS Manual on Page 115