Whats Up in the Sky May 2005
History shows a woman’s place is in outer space
Remember the old Beach Boys’ lyric, “And she purrs like a kitten till the lake pipes roar”? They were referring, of course, to their little deuce coupe. For centuries men have been referring to ships and machines with feminine pronouns. Although not as common anymore, there was a time when the most famous computers were, literally, women.
Maria Mitchell was America’s first well-known woman astronomer. On Oct. 1, 1847, while her parents entertained dinner guests downstairs, she discovered a comet. At one point in her career she worked as a computer (one who performed lengthy mathematical calculations) for 19 years out of her home, calculating positions of Venus.
In 1875, three women were hired to work at the Harvard College Observatory performing the involved mathematical computations necessary to calculate orbits, measure positions and brightness of stars, and classify stellar spectra. Due to an increasing number of photographic plates exposed through the telescopes, the observatory needed helpers to search the plates and perform long, detailed calculations to determine the information about the stars recorded on them. In the notions of the day, women were considered ideally suited for such routine, meticulous, and tedious work (men being better suited to creative projects). And, since a woman could be paid considerably less than a man, three or four times as many assistants could be hired for the same amount of money. Between 1877 and 1919, a total of 45 women were employed by the Harvard College Observatory to work as “computers.”
Some very important discoveries were made thanks to the work done by these women. Annie J. Cannon established the system of classifying the spectra of stars that, with minor modifications, is still in use today.
Henrietta Leavitt may have made the most significant discovery of all the women computers. Leavitt discovered a property of certain stars that vary in brightness, known as the Period-Luminosity Relation, that allows astronomers to determine the star’s actual brightness, or luminosity, by measuring how long one bright-dim-bright cycle takes. (Such stars are known as Cepheid variables). By comparing the real brightness of a star with how bright it appears, astronomers can determine the distance to the star. (You do the same thing when you drive at night and see headlights approaching). Her work led to fundamental improvements in our understanding of the size of our own galaxy and, ultimately, to the discovery of the expanding universe.
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Here are this month’s viewing highlights:
- May 1 and May 30: Last quarter moon
- May 8: New Moon
- May 9: using binoculars, look WNW to see Venus below the crescent moon; also look for the star Aldebaran and the Pleiades cluster to Venus’ left and right, respectively
- May 16: First quarter moon
- May 24: Full Moon occults Antares – 4:00 a.m.
- May 31: two hours before sunrise look for Mars right above crescent moon in ESE
- Planets this month: Jupiter, the brightest object in the sky after the moon, dominates the southern sky throughout the month; Saturn sinks in the west as the month progresses; Mars is in the southeast at dawn; Venus follows the sun over the western horizon and becomes easily visible by month’s end.
Peter Burkey is president of the Shoreline Amateur Astronomical Association and has been an amateur astronomer and astrophotographer for 25 years. He also taught astronomy at Fennville High School from 1981 to 2003.
Peter Burkey – SAAA President
