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Chang K'ien
Minister to Wu Ti

There is a marvelous story from Chinese legend about the Goddess of Weaving, Chih Nü, and her beloved, Ch'ien Niu, a handsome young shepherd in the Emperor’s household. This myth tells of the separation of the two by royal decree, with the final provision that only on the seventh day of the seventh month might the two lovers meet. It seems that on that day all the magpies of the world gather to form a bridge across the river of heaven with their wings; and on that bridge Chih Nü may cross. Chih Nü is Vega; Ch'ien Niu is Altair, the Eagle of our constellation Aquila, lying across the river of heaven, the Milky Way. This story was repeated in the September, 1995, issue of the Refractor.

There is another story from the Far East that confirms this tale. The account begins two thousand years ago, in the Han Dynasty, when it was supposed that the Yellow River had its source in the Milky Way. The emperor Wu Ti determined to know the truth, and he selected the courtier Chang K'ien, an able and experienced adventurer, to sail upstream to the headwaters of the Yellow River.
Chang K'ien set out, and he sailed for several moons, past farms and villages, through fine weather and foul, through narrow gorges and through placid waters, following the river as it twisted its way, always to the west. At length, he came to a place like no other; and when twilight came the night remained bright, more brilliant than under a full moon. The stars did not twinkle and they seemed exceedingly near. He recognized none of the constellations he knew so well.

He saw no people as he sailed along; but he did find a paradise of fragrant trees, with rainbow-winged birds happily singing among the branches. He caught a glimpse of the rabbit of the moon, and as he traveled onward, he passed the great beasts who ruled the four quarters of the sky: the blue dragon, the scarlet bird, the black tortoise and the white tiger.

Finally, Chang K'ien noticed a beautiful young maiden, along the bank of the river, weaving a magnificent tapestry of iridescent colors on her loom. He stopped and asked her where he was, for he was surely beyond the Han empire of Wu Ti.

The maiden smiled and shook her head. She replied, “Take this shuttle from my loom and return to your own city. Show it to Kün P'ing, the astronomer, and tell him of your travels. He will tell you where you have come to.”

Chang K'ien made the arduous journey down the river, and, on his return to the court of Wu Ti, he requested that he be allowed to see Kün P'ing. He gave the shuttle to the most learned man, who studied it with curiosity and amazement.

“There is no doubt,” the astronomer said. “On the seventh day of the seventh month I was observing the annual meeting of the Weaving Goddess Chih Nü and the Herdsman Ch'ien Niu, when I also saw a guest star come between them. I wondered about it, but now it is certain that the stranger star was you, sailing on the celestial river.”

The bright star Altair forms one vertex of the familiar Summer Triangle, together with Deneb in Cygnus and Vega in Lyra. Long ago, the constellation of Lyra was known as a vulture. It is possible that in ancient times, these were identified as the three Stymphalian birds, man-eating beasts with claws of iron, that Hercules faced in the sixth of his twelve labors.

Aquila, Cygnus and Lyra (as the vulture) are among several birds represented in the mythology of the heavens. The early seventeenth-century German astronomer Johann Bayer, the first to publish an organized chart of the constellations, the Uranometria, added the southern constellations Grus, the crane, Tucana, the toucan, Avis Indicia (now Apus, the bird of paradise), Pavo, the peacock, and the miraculous Phoenix. Columba, the dove, was not established until 1679, by Augustin Royer.

Altair is the brightest star in the constellation, and it is easily recognized, accompanied on either side in a straight line by Alshain and Tarazed (Beta and Gamma Aquilae). Altair is a remarkable star. It is one of the nearest of the bright stars, and it has a large proper motion. It is also known for its exceptional rotational rate. As measured by Doppler shifts, it turns more than three times in one of our days, compared to one turn in 25 days for our Sun.

For some time, in 1918, Altair was only the second brightest star in Aquila, for on the night of June 8 Nova Aquilae 1918 appeared with a brilliance second only to Sirius in the entire sky. By the following spring, however, the nova had faded below naked-eye visibility. Other novas have appeared more than eight times in Aquila during the last hundred years. Perhaps there was indeed a guest star there during the Han Dynasty.

Eta Aquilae is a supergiant Cepheid variable which brightens from magnitude 4.4 to 3.5 and dims again with a period of just over a week’s time. For binocular viewing, there is an open cluster of stars, NGC6709, seen against a rich background of Milky Way stars. There are several fine multiple stars and planetary nebulas for appreciation in a small scope.

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