Northern Hemisphere gazer's guide

Aug 6-7: The moon passes Venus closely at about 9 p.m., EST, on the 6th, so close that it coves the exceptionally bright planet over parts of Africa and Asia, but not north America. The moon will be close to the planet in our skies on both mornings, above and to the right of Venus on the 6th, below and to its left on the 7th. You can see them from just before dawn until just before sunrise, above the eastern horizon.

Aug. 10: An annular solar eclipse occurs today in a path crossing central South America. During an annual eclipse, the moon's shadow points toward Earth, but the moon is more distant from Earth than the length of its shadow. As a result, the moon appears in our sky slightly smaller than the sun, and when it is situated centrally in front of the sun it leaves a thin ring of the sun visible around the moon. This ring, or annulus from the Latin, gives its name to the kind of eclipse that takes place. If the moon were a bit closer, it would cause a total solar eclipse. In any case, a partial eclipse occurs in a much wider area on either side of the annular eclipse path. For this event, the area of partial eclipse includes all of South and Central America, southern Florida, Southern and Southwestern United States, and Hawaii.

Aug. 10-13: These are the best mornings for viewing the famous Perseid meteor shower, the most reliable, productive, and easy-to-observe shower of the year. Viewing is best early in the morning, from 1 o'clock on, when Earth has turned us in the direction from which the meteoroids are coming, adding our rotational and orbital velocites to the velocity of the incoming particles. Thus entering Earth's atmosphere at a faster speed, they are brighter. The best morning for the Perseids should be the 12th, when you can expect to see up to 50 shower meteors per hour. For one or two mornings before and after, you should see about 25 per hour, many quite bright. For best viewing, find a reclining chair or some other support to help you lie with your head positioned to see as much of the sky as possible. The shower meteors, even though they seem to radiate from the constellation perseus, may appear in any part of the sky. After you have seen one or two, you will become more adept at finding them.

Aug. 12: Tonight may be your last chance to see Jupiter as an evening star during this cycle. It is very low in the west at dusk, setting soon after. But the moon can guide you to it, a slim crescent of the young moon, with Jupiter just below it. In Arctic regions, the moon covers Jupiter (an occultation) about 4 p.m., EST.

Aug. 15: The moon is at apogee, where it is farthest from Earth.

Aug. 25: During today's full moon, a penumbral lunar eclipse will occur while the moon is above the horizon in North America. A penumbral eclipse occurs when the earth only partly obscures the sun from the moon's surface. Seen from Earth , there is a slight darkening of the normal full moon's brightness, but it is gradual and without abrupt change. The light on the moon also appears to be more pale and flat, reflecting the fact that there is much less contrast at such a time between the bright and dark parts of the moon's surface. Mid-eclipse, when the light on the moon is weakest, occurs at 10:30 p.m., EST.

Aug. 27: The moon is at perigee, where it is nearest to earth this month.

All month: Venus is now a spectacular morning star, rising in the east about 3 1/2 hourse before the sun and moving well up into the southeast before it fades from view about half an hour before sunrise. Its position improves during the month, as it approaches its maximum angular separation to the sun's right (greatest westerly elongation) on the 24th. The waning crescent moon joins it on the mornings of the 6th and 7th. During the first week or so in August we may still be able to find Mercury as a morning star also, low in the east about half an hour before sunrise. But it is dimmer than it was at the end of July.

Our great evening stars of last winter and spring are making their "last hurrah." You may still see Jupiter emerge out of the sunset glow for the first week or so, especially with the young crescent moon to help you on the 12th, but thereafter it will be just too late to see it when the evening sky darkens in the west. It will have set. Saturn is behind it by about half an hour, but much dimmer, so you won't see it until the western sky grows much darker, and by then it will be near the horizon. You probably won't be able to see it after conjunction with the moon on the 13th. Mars is still farther behind, setting about an hour and a half after Saturn, but it is also very dim. Look for it below the moon on the 15th, above Spica (in Virgo) on the 17th.

The sun is in the constellation Cancer in early August, moving into Leo during the second week. Mercury moves out of Gemini, through Cancer, and into Leo; Venus leaves Taurus, passing briefly through part of Orion and into Gemini; Mars is in Virgo, Jupiter in Leo, Saturn in Virgo, Uranus in Libra, Neptune in Ophiucus, and Pluto in Bootes.

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