Sky Events

(revised 11/16/08)

Planets. Jupiter and Venus are starting to approach one another more and more rapidly, as Jupiter sinks and Venus rises in evening twilight. They'll meet on December 1, and the crescent Moon will be nearby. More information here at the time.

International Space Station (plus the Shuttle). The International Space Station (more info here), the largest satellite in orbit and the only permanent one inhabited by human beings, is occasionally visible to the naked eye. It looks like a moving star. Its brightness varies, but it can rival the brightest planets and outshine the brightest stars when conditions are optimum.

The Space Shuttle Endeavor is currently docked at the ISS (making it a bit brighter than usual). Here are some good (meaning generally bright) passes coming up.

Thursday, Nov. 20, 6:14-6:16 p.m. Rises in the southwest (SW); reaches maximum altitude* very high (altitude* 83 degrees, nearly straight up) in the NW (though you can scarcely define directions for such a high pass); disappears in the Earth's shadow shortly thereafter. Magnitude* -2.4, or the brightest pass in this set. Don't miss it!

Friday, Nov. 21, 5:05-5:10 p.m. Rises SSW; peaks fairly low (28 degreees altitude) in SE; sets ENE. Magnitude -1.0, or much fainter than yesterday's pass (but still brighter than any visible star).

Saturday, Nov. 22, 5:30-5:35 p.m. Rises WSW; peaks high (73 d) in NW; disappears low (16 d up) in NE. Mag. -2.2, or nearly equal to Thursday's pass.

Monday, Nov. 24, 4:47-4:52 p.m. Rises WSW; peaks fairly high (65 d) in NW; sets NE. Mag. -2.0.

There are other, fainter passes visible during this time period. For more information about the ISS, and about other satellites' appearances, look at Heavens Above.

* Altitude: angular distance in degrees above horizon, NOT distance in miles above Earth's surface. Straight overhead is 90 degrees, halfway up the sky is 45, the horizon is 0.

  Zenith: the point straight overhead.

  Magnitude: brightness. The brightest star in the winter sky, Sirius, has a magnitude of -1.4 (negative numbers are brighter); the brightest summer star, Vega, is at 0.0. Jupiter stands at -2.5, Venus at -4.0. The faintest star visible to someone with excellent eyesight is around +6. The Sun is -26! Magnitude estimates for the Station and Shuttle are typically underestimates: they usually appear significantly brighter than the numbers would lead you to expect. Also note: an evening pass starts out quite dim (because the Sun is shining mostly on the part of the spacecraft facing away from us). The satellite becomes brighter as it reaches its peak altitude. So have patience: don't give up too soon! Sweep your eyes along the expected path; look for a moving dot that doesn't blink. Morning passes start out a bit brighter, so are easier to pick up right away.

  Weather conditions: as I tell my students, I can't be held responsible for anything that happens less than 100 miles above the Earth's surface.

Star charts, sky maps. One of the most comprehensive star charts available is at SkyMaps.com.

Questions about this page? Contact the planetarium director.

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