Aug 01

August 2006

Whats Up in the Sky August, 2006

A Tribute to the Instruments of Space Exploration?

Do you remember the Top-40 single that was named after a satellite? I was reminded of it when I saw the Space Shuttle on the news recently. Remember when we knew the names of satellites and spacecraft because they were in the news?

The most famous satellite is probably Sputnik 1 because it was the first human-made object to orbit the earth. Other spacecraft, such as Mercury, Apollo, Voyager, and the Hubble Space Telescope are fairly well known, but lately a bevy of less familiar spacecraft have been making some amazing discoveries.

For example, the Galileo spacecraft studied the planet Jupiter and its moons for over 14 years, making many discoveries. Ulysses studied the polar regions of the sun and was the first spacecraft sent out of the plane of the earths orbit. The Mars Global Surveyor has studied the entire surface of Mars and has sent back more data about the red planet than all other previous missions combined. Mars is also currently being studied by the 2001 Mars Odyssey and the two tremendously successful Mars Exploration Rovers, Spirit and Opportunity. These two workhorses have all but confirmed the theory that ancient surface water once flowed on the planet.

Cassini-Huygens, with a record number of twelve instruments, has been studying Saturn since June 2004. Discoveries include ice geysers on one of Saturns moons, and details of the atmosphere of Titan, its largest moon, on which the Huygens probe successfully landed. Even distant Pluto will soon (2015) be visited by the New Horizons probe.

The Stardust spacecraft rendezvoused with comet Wild-2, passed through the comets coma where it collected cometary dust, and returned the sample last January, an amazing accomplishment! We’ve even landed a spacecraft (NEAR Shoemaker) on an asteroid (Eros).

The aforementioned Hubble Space Telescope has been joined by the Chandra X-ray Observatory, the Spitzer Space telescope, and the Compton Gamma Ray Observatory. Known as NASAs Great Observatories Program, the instruments are designed to cover the majority of the electromagnetic spectrum.

All of these instruments, and more, have contributed greatly to our understanding of everything from the formation of planets to the fate of the universe. We’ve learned quite a bit since Telstar.

I recently wrote about observing phenomena involving the moons of Jupiter. On the evening of Sunday, August 6, start observing Jupiter (low in the southwest) as soon as it gets dark. Three of its moons are easily visible, but a fourth one, Europa, is probably not visible because it is in front of Jupiter and lost in its glare. A little after 11:00 p.m. it emerges into view along the left-hand side of the planet (as viewed in most telescopes) just as its shadow is entering the planets disc from the lower right. Meanwhile, Io, the lone moon on the right side of the planet, moves closer and closer until it, too, crosses in front. You will need a good telescope and a clear view of the horizon to do this observation.

Here are this months viewing highlights:

Planets this month: Jupiter is still visible in the SW evening sky. Venus low in ENE before dawn, lower at end of month. Venus is joined first by Mercury, then by Saturn in the predawn sky.

August 2: First-quarter Moon.
August 2: Venus is 5.5° above Mercury – look near the eastern horizon one hour before sunrise.
August 9: Full Moon.
August 10: Mercury now only 2° below Venus.
August 12: Waning gibbous moon spoils peak of Perseid meteor shower.
August 15: Last-quarter Moon.
August 22: Use binoculars to see Mercury, Saturn, and Venus next to thin crescent moon 30 minutes before sunrise.
August 23: New Moon.
August 26: Venus and Saturn separated by about one full moon diameter.
August 31: First quarter Moon just below star Antares, low in SSW one
hour after sunset.

Peter Burkey – SAAA President