Scheduled air date: 2000 Aug 28-Sep 03
During late evening for the next couple of weeks, the Summer Triangle can be seen nearly directly overhead. This popular asterism is formed by stars from three constellations: Vega in Lyra, Deneb in Cygnus and Altair in Aquila.
Vega—the brightest star in the Summer Triangle—will be the "North Star" in about 12,000 years, instead of present-day Polaris.
This change in pole stars is caused by precession, the very slow (26,000-year cycle) wobble of the Earth's rotational axis. The illustration above shows the apparent path of the pole with corresponding years labeled for the present cycle.
If you wish to view illustrations for other episodes, please see our Star Gazer Illustrated directory.
|Illustrations on this page were created using
Software, an advanced desktop planetarium program designed for Windows.|
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