September 22, 1999
1. October sky. Other than the title of a fine movie, this phrase conjures up a wonderful image of long, cool, clear nights for glorious sky gazing. The leading roles in the upcoming evening performances will go to the true giants of the solar system, Jupiter and Saturn. Be watching as they clear a late-evening eastern horizon near you.
2. How many of us notice the moon's nightly changes? From one night to the next, the moon's position will change against the background of stars by nearly 15 degrees, the projected width of your outstretched fist. In addition, the moon rises about one hour later each night. With last quarter phase at 11:02 p.m. yesterday, the moon can be expected to clear the eastern horizon no earlier than 2 a.m. tomorrow.
4. In 1957, the skies of October carried a nightly reminder of dread and uncertainty, all brought about by a Soviet spacecraft launched on this date to orbit the Earth and do little more than broadcast a pinging signal. With hundreds of Earth-orbiting satellites in the sky now, it may be hard for us to appreciate how intimidating Sputnik I was to Western societies.
5. By now, many households are adjusted (resigned?) to early hours on school mornings. Plan a treat for yourself and get up a few minutes earlier to enjoy a view of the eastern horizon at about 6 a.m. The sun isn't up yet, but Venus, the waning crescent moon and Leo's brightest star, Regulus, are joined in a charming conjunction.
9. The moon has progressed through waning crescent phase to disappear altogether for new phase at 6:34 a.m. There's no possibility of an eclipse as the moon is a couple of degrees north of the sun's position. The sun will obscure its stellar background, but its path is presently crossing through the zodiac constellation Virgo.
10. Computer programs can recreate the skies of another time for us. On this night in 1846, for example, just a few weeks after the first deliberate sighting of the planet Neptune, English amateur William Lassell would have had a stunning view of Saturn and Neptune above the southern horizon. Lassell was the first to see Neptune's brightest moon, Triton.
12. If you look for the Big Dipper to check directions, you may have a little trouble these late autumn evenings. Ursa Major is below the pole and will only be high in the sky towards dawn. This does mean that another northern constellation, Cassiopeia, is ideally situated for evening view. Look for this "W"-shaped pattern of stars about 50 degrees above the north-northeast horizon.
15. We're witnessing the last of Mars' great 1999 season. Before the evening sky is truly dark after sunset, Mars and the moon are near the western horizon. Mars has faded in brightness as it pulls away from Earth so that it barely outshines its stellar background, the stars of Sagittarius and Scorpius.
17. The moon will be at first quarter phase at 10 a.m., although Earth's partner world won't clear the Kansas horizon until mid-afternoon. Tomorrow will be the 40th anniversary of humankind's very first look at the moon's far side, transmitted by the Soviet spacecraft Luna 3. The far side of the moon never turns to face Earth in its monthly orbit and is reasonably different than the side we see - more mountains and very few of the flat basins that we call "seas."
19. If Cassiopeia is in prime view, can Perseus and Andromeda be far away? In one of the most enduring associations of star patterns and mythical stories, Cassiopeia is the queenly mother of the unfortunately chained maiden, Andromeda. Luckily, the heroic Perseus will be able to rescue her, with the help of his winged steed, Pegasus. Just how these story lines figure into the star patterns you see is a little tough to follow. Cassiopeia's recognizable "W" shape corresponds to the throne upon which the queen sits.
23. Jupiter is at opposition today, which means that it is 180 degrees from the sun's position - Earth stands squarely between the sun and our largest planet. That pretty well describes our position with respect to the moon, too. You'll find the nearly full moon in Pisces, with Jupiter and Saturn off to its left as you face southeast.
24. What a beautiful treat! The moon is full at 4:02 p.m., placing it in the best configuration for all-night viewing. The moon will be flanked by Saturn on the left and Jupiter on the right. By tomorrow, the moon will have moved to the east of both planets.
25. Perhaps William Lassell could get time off in the month of October? Planetarium software can show us the features of the sky on Oct. 24, 1851, when Lassell discovered two of Uranus' moons, Ariel and Umbriel. Once again, Saturn was a near neighbor to the fainter planetary target, but Lassell wouldn't have had to worry about any moonlight. In our own time (as in, tonight!), Saturn will be four lunar diameters, or about two degrees, north of the moon.
26. As the moon rises later each night, it passes through a more easterly zodiac constellation each evening. If you look for the rising moon near midnight tonight, you will catch it within the boundaries of the Hyades star cluster, which makes up the "V"-shaped part of the constellation Taurus. Taurus' brightest star, Aldebaran, is part of this pattern of stars.
31. The moon is at last quarter at 6:04 a.m., so there will not be any moonlight to assist trick-or-treaters as they scour their neighborhoods for candy. You should have changed your clocks last night, so it will be getting dark at an earlier clock hour. You can still see Venus in pre-dawn east, even though "pre-dawn" now means 5 to 6 a.m. Venus is at its greatest angular distance from the sun today.