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.

Tuesday, August 19, 2008

Earth’s Seven Sisters are out this Week

Earth’s Seven Sisters are out this Week
by Dave Adalian

All seven of Sol’s other planets are out this week, and with a little luck and patience earthbound planet hunters will be able to collect them all.

Tonight (Aug. 21, 2008) is the night to be lucky -- and careful -- to find the first target. Saturn follows the sun over the western horizon about 30 minutes after sunset, making it a difficult target for the naked eye.

Because it’s bright, Saturn should turn up in the reddened western sky glow. For safety sake, start searching for the ringed planet only after Sol’s disk has completely disappeared. This is especially true when using binoculars: Viewing the sun through optics will cause vision loss.

If Saturn won’t cooperate tonight, Friday and Saturday are also possibilities, but chances of seeing the sixth planet grow slimmer each night.

After the search for Saturn, finding Venus and Mercury will be a breeze. (Well, easier anyway, but because they’re so low the search might still require the aid of binoculars.)

The innermost planets are in close conjunction for the next few days, and can be seen together above and to the left of where the sun met the horizon at sunset. The pair may also help locate elusive Saturn: it will be between the pairing of the first and second planets and the sun.

Follow that imaginary line connecting Sol, Saturn, Mercury and Venus -- the ecliptic -- further up and to the left to find ruddy Mars. The Red Planet is now so far away it’s little more than a reddish pinpoint, but like all the planets it doesn’t twinkle. Again, binoculars will help.

King Jupiter is impossible to miss, shining bright in the south on the shoulder of Sagittarius the Archer after sundown. The only reason for binoculars here is to search for the planet’s larger moons.

Binoculars will be a must to find Neptune, the eighth planet out. Look for Neptune’s tiny blue-green disk about halfway up the sky due south at 30 minutes after midnight tonight. After Pluto’s demotion, Neptune is now the farthest planet out.

Closer in but farther out along the ecliptic at present is the seventh and final planet, Uranus. It will be due south about 2 a.m., and can be seen with the naked eye. Because Uranus is at the edge of the eye’s range, binoculars will help you locate it. A finder chart will make finding both Uranus and Neptune much easier.


This column was originally intended for publication in the Visalia (Calif.) Times-Delta and Tulare (Calif.) Advance-Register in August 2008. For some reason that didn't happen. I don't know why. So, I wrote them another one, which is the next post after this.