Go Stargazing! August Edition

Jupiter is up all night long this month.  On August 14, the Earth passes between Jupiter and the Sun.  This alignment is called ‘opposition’ because it places Jupiter opposite the Sun in our sky, making it visible from dusk to dawn.  Tonight, Jupiter rises just before 9 p.m.—in late twilight.  It could take some time for Jupiter to clear trees or buildings around your observing site.  Soon, however, Jupiter will be already in the sky even as night is falling.  Face southeast and look for the brightest point of light there.  Early risers can still see Jupiter in the southwest before dawn.  Remember, Jupiter outshines everything in the sky except the Sun, the Moon, and Venus, so if you’re looking in the right direction, you can’t miss it.  

Venus is a dazzling morning star this month.  Look east right as day begins to break for the brightest thing unless the Moon is nearby.  Venus remains the ‘morning star’ for the rest of 2009.  Mars is a little higher in the east at dawn than it has been.  Still, it remains fairly dim.  Look for Mars above Venus in the east. 

is now low in the west at dusk, and will become difficult to observe by mid and late August.  The rings continue to appear thinner and thinner as Earth continues to align with Saturn’s ring plane, making the rings appear edge-on from our perspective.  On September 4, the Earth is exactly in Saturn’s ring plane, and the rings actually vanish from view!  It turns out, though, that Saturn is too close to the Sun in our sky on that date; the Earth will be about to pass on the far side of the Sun from Saturn.  No one can get a good look at Saturn this September.  Still, we can watch through our telescopes as Saturn’s rings appear thinner and thinner throughout August.  Since we’re seeing the rings edgewise, Titan and other moons have been passing in front of and behind Saturn’s disk.  This happens again on August 18, when Titan transits (passes in front of) Saturn’s disk.  By August 18, however, Saturn is so close to the Sun in our sky that it is only about five degrees high during late twilight and sets before night completely falls. 

Saturn
Creative Commons License photo credit: Elsie esq.

Saturn

The Big Dipper is high in the northwest on summer evenings.  From the Big Dipper’s handle, you can ‘arc to Arcturus.’  Arcturus, in the west at dusk, is the fourth brightest star we ever see at night and will be the brightest star in our evening skies during all of August. Continuing the curve of the Big Dipper’s handle past Arcturus, you can ‘speed on to Spica,’ a star lower in the southwest at dusk.  Spica is a stalk of wheat held by the constellation Virgo, the Virgin, who represents the harvest goddess.

Milky Way and a meteor?
Creative Commons License photo credit: madmiked

In the south as night falls is Antares in Scorpius, the Scorpion.  This is a red supergiant star about 700 times as wide across as our Sun.  To the Scorpion’s left, look for eight stars in the shape of a teapot.  These stars are the bow and arrow of Sagittarius, the Archer.  High in the east, the Summer Triangle dominates the evening sky.  The Triangle is up all night long until mid-August.  Vega is the brightest of the triangle’s three stars, followed by Altair in Aquila and Deneb in Cygnus.  Rising in the east on August evenings is the Great Square of Pegasus, heralding the upcoming autumn. 

Moon Phases in August 2009:

Full                                    August 5, 7:55 pm
Last Quarter                  August 13, 1:55 pm
New                                   August 20, 5:01 am
1st Quarter                     August 27, 6:41 am 

The Full Moon of August 5 almost enters the Earth’s shadow.  It does skirt the edge of the penumbra, in which the Earth partially blocks the Sun.  The resulting penumbral eclipse is scarcely noticeable at all, however.  When there is a central solar eclipse, as occurred last month in Asia, there are often penumbral (or very short partial) lunar eclipses two weeks before and after. 

Perseid Meteor
Creative Commons License photo credit: aresauburn™

The Perseid meteor shower peaks on the morning of August 12.  Our George Observatory will be open on the night of August 11-12 until dawn for observing the meteors.  Keep in mind that instead of the meteors running into the Earth, Earth is running into the meteors.  Thus, the leading edge of the Earth—the side going from night into day—sees more meteors.  This means you’ll see more meteors towards dawn than at dusk.  The Perseid shower averages about 2 meteors per minute each year, but this year a large waning gibbous Moon will hide many of those shooting stars from us.  If you observe the shower anywhere near a big city, light pollution will hide even more. 

The following Friday, August 14, is Members Night at the George Observatory.  The Perseid shower and the Members Night are events 63 and 64 of our Fun Hundred events to celebrate the museum’s 100th anniversary.

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