Wednesday, August 27, 2008

Triple conjunction challenges eagle-eyed planet hunters

Triple conjunction challenges eagle-eyed planet hunters
by Dave Adalian

The next two weeks present a challenge for planet hunters in possession of either keen eyes or a pair of binoculars. Those who take up the difficult task will also need an unobstructed view of the western horizon and patience.

About half an hour after sunset tonight, Venus should be obvious to the naked eye directly west and around 10 degrees or about two hand-widths above the horizon in sunset’s afterglow.

The most eagle-eyed might also see dimmer Mercury shining in the gloaming less than a hand-width to the left of Venus. Those of us without such keen vision will have to resort to binoculars. Just about any will do, though a magnification of at least seven times is recommended.

But, even those with the sharpest of eyesight likely won’t find dim Mars just two hand-widths above and to the left of the Goddess of Love. For that, binoculars are a must, but the extra effort will be worthwhile as this trio draws into an ever tighter triangle during the first half of September.

While the God of War is still about 10 degrees separate from the Goddess of Love, by next Wednesday the distance will be half that. Four days later on Sept. 7, Venus and Mars will be only 2.5 degrees apart. The gap will be only 1.75 degrees the next night, and a mere 1.5 the night after that.

On Sunday, Sept. 10, the two planets will appear less than a single degree apart, and on Sept. 11, when the two are at their closest, only three-tenths degree separates them.

During the close call on Sept. 11, when Love and War appear almost on top of one another, remember they’re really millions of miles apart. Though they look close enough to collide, Venus is 138 million miles away from Earth, while Mars is 227 million miles distant.

Mercury, meanwhile, is a relatively close 88 million miles away from Earth.

While this triple conjunction unfolds, the trio will be setting earlier night to night, so by the end even the keenest of eyes will need binoculars to follow the show. Just don’t point them at the sky until after sunset to avoid eye damage.

For a beautiful bonus look for the new moon near the trio on Sept. 1, when it will hover just above the horizon but below the planets, and again on Sept. 2, this time off to their left.


This column originally appeared in the Visalia Times-Delta and Tulare Advance-Register in August 2008.

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