Stargazing: Eagles and Cosmic eyes

The noble eagle Aquila has been making its southward journey as winter approaches. Seen in the west before sunset, this constellation is part of Greek mythology as the eagle carrying the thunderbolts of Zeus. Its brightest star, Altair, gets its name from an Arabic word translating to “flying eagle.” Babylonians and Sumerians referred to Altair as “the eagle star,” which marks the southernmost corner of the three stars making up the summer triangle.

Within the borders of the Eagle glows an unusual planetary nebula. At about 6,500 light-years from Earth, the round-shaped gases shine like an eye in the night, earning the nickname Glowing Eye Nebula. Planetary nebulae are clouds of gases ejected from a central star as it nears the end of its lifespan. Ultraviolet radiation from the blazing stellar core lights the gas shells.

German astronomer Albert Marth, who also worked in Britain and Ireland, discovered NGC 6751 in 1863. But it was Scottish astronomer Williamina Fleming who, in 1907, while working at Harvard University, recognized the specific nature of the planetary nebula. Previously a teacher in Scotland, Fleming earned a living as a housekeeper to Edward Pickering. He then hired her and several other women as “computers” to catalog collected images. Among cataloging over 10,000 stars in 9 years, Fleming discovered more than 310 variable stars and 59 nebulae, including the well-known Horsehead Nebula.