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Skylights featured nine times on Earth Science Picture of the Day: 1 2 3 4 5 6 7 8 9


Photo of the Week. Roses salute the blue sky.

Astronomy news for the week starting Friday, August 7, 2009.

Most of the week sees the waning gibbous Moon, which, rising ever later before midnight, finally reaches its third quarter on Thursday, August 13, during daylight hours, but just after Moonset in North America. The morning of Friday the 14th, we then will see the first part of the waning crescent. The Moon's only planetary passage is well to the north of Uranus on Sunday the 9th.

Since last March, we've watched Jupiter first coming on to the scene, then rising ever earlier until early last June it began rising after local midnight. It now comes full bore onto the nighttime sky, as the giant planet passes opposition with the Sun during the day on Friday the 14th, making the view on the nights of Thursday the 13th and Friday the 14th about equal. On these nights, Jupiter will rise at sunset, set at sunrise, and cross the meridian to the south at local midnight (1 AM Daylight Time). With the Earth passing right between Jupiter and the Sun, the King of the Planetary System is also in maximum retrograde motion, to the west against the background of the relatively faint stars of northeastern Capricornus, to the north of Nashira and Deneb Algedi (Gamma and Delta Capricorni) as well as just to the southwest of Neptune, which passes opposition with the Sun next week.

While Jupiter dominates the scene, Saturn, which sets in late twilight, slips away. It'll be back in the morning sky in mid-October. Mercury, now in the west and setting in mid-evening-twilight, is an even tougher find. The current mornings are now reserved for Venus and Mars. The red planet, now mid-first magnitude and rising around 1:30 AM Daylight, will be heading toward the horns of Taurus (Beta and Zeta Tauri) as if they were a pair of goalposts. With Mars now rising earlier and Venus rising later, the gap between the two of them grows. Brilliant Venus, though, remains a most excellent sight as it comes up just after 3 AM near the feet of Gemini to the southwest of Castor and Pollux.

The biggest event of the week is the return of the annual Perseid meteor shower, which in North America peaks during the daytime of Wednesday the 12th, making the mornings of the Wednesday the 12th and Thursday the 13th the times to watch (mornings far better than evenings). Even though the third quarter Moon will light the sky, you should be able to see a few meteors. While the meteors seem to come out of Perseus, the best direction to look is overhead. The shower is from the leavings of Comet Swift-Tuttle, which has a 130 year period around the Sun and last came by in 1992, so the shower is diminishing some.

Some of the great constellations lie in the far south and are thus almost invisible to people in the northern hemisphere unless they have great horizons. Think, for example, of winter-spring's Argo, with only Puppis (the Keel of the Ship) readily visible to northerners to the southeast of Canis Major and Sirius. In the northern summer, we have Centaurus, the Centaur, which lies south of Virgo's Spica and to the west of Scorpius, with Lupus in between. From the southern hemisphere, Centaurus is glorious to the east of Crux, the Southern Cross.
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