Explorit Science Center

AT EXPLORIT ON SATURDAY MAY 25 AT 7:30 P.M.

CLUB EVENTS

Come to our next meeting, at 7:30 p.m. on MAY 25TH at Explorit. The evening's topic will be "DIPPER FINDERS AND STAR CLOCKS". Ancient stargazers could tell time during the day using the Sun's shadow on a Sundial. But after the sun had set what could they have used? One answer is "A Star Clock"! By making a simple star clock from paper and, if you can see the North Star (Polaris), you can tell the hour quite easily. At this meeting we will discuss clocks and calendars and how they are tied to the motion of the Earth around its axis (daily) and around the sun (yearly). For those of us needing help finding the North Star, we will also make "Dipper Finders". So, come to our meeting, make a Dipper Finder, make a Star Clock and then lets go outside to see what time it is!

APRIL'S MEETING We had an exciting demonstration of how craters are made by meteors colliding with the surface of a planet or a moon. In this case, the meteors were pebbles that plowed into a kitty litter box filled with flour that had been lightly dusted with powdered chocolate drink mix. The meteors were personally selected and propelled by our two youngest members in attendance: Clark and Erik. Preceding the demonstration was a slide show on the features of craters (central peaks, collapsed walls, rays and secondary impacts). The sky was clear and we observed craters on the Moon and the phase of Venus through two members' telescopes--thanks to Don, Maria and Tim for their help.

COMET HYAKUTAKI Our spectacular visitor from the frigid depths of space sped to its closest point near the sun (21 million miles) on May 1. Now beginning its voyage back to the cold spaces beyond Pluto, it will be well placed for observation in the southern hemisphere. However, and unhappily for observers in Australia, Africa and South America, early predictions are that it will not be as bright as when we saw it in April. The Comet of 1996 will return again in 14,000 years--I wonder who or what will view its return?

DAVIS FORECAST: CLEARING. Noticed many clouds these past evenings? According to Guy Ottewell's Astronomical Companion (1979) the months of May through October are special in California's central valley, including Davis. During these months we have fewer cloudy days than almost any other area within the continental U.S. If you are hoping to avoid clouds, your best month for observing from the Central Valley is July, when clear skies dominate 86 to 90 percent of the time. Note this information was based on Sacramento weather station observations and from other weather stations across the U.S. between 1940 and 1971, and refers to daytime observations only. Here's wishing you many clear evening skies this summer!

WHAT'S "UP THERE" IN MAY? May belongs to Venus. This evening "star" reaches its greatest brilliance on May 4 but continues to dazzle the eye for the remainder of May. Now is the time to observe Venus through binoculars because its crescent shape should become quite apparent even in the usual 7X binocular field of view. Telescopes trained on this lovely planet should look for shadings on the crescent and, after dark, try to observe the 'ashen light' on the dark part of the disk. Venus shares the evening sky with no other planet, though Jupiter can be seen above the southern horizon just before dawn. Saturn is near the sun in the pre-dawn sky, while Mercury and Mars are all but lost in the glare of the rising sun.

VESTA. Binoculars will help you find the brightest known asteroid, Vesta, which is at opposition (that is, we are between it and the Sun), early in May. From our vantage point, it will "spend the summer" in the constellation Libra, nearly circling the star Beta Librae (Zubeneschamali) from May to August. For the first half of May, it will be "above" (north) of the star, moving to the "right" (west) through the middle part of June. Vesta is the only "minor" planet that can ever be observed by the unaided eye--it is approximately 310 miles across at its widest point.

Sources: Astronomy Magazine, Sky and Telescope Magazine, Abrams Planetarium diary website: http://www.pa.msu.edu/abrams/diary.html and RedShift 2 CD ROM.

The Astronomy Club is hosted by Dennis Smith with the assistance of Tim Feldman and other eager astronomy buffs. The club is for everyone - adults, children, knowledgeable or ignorant. Come to listen, look and learn, or to share your expertise or experience.