Sky at a Glance | August 17th, 2007

By: Alan MacRobert August 17, 2007 0

Some daily events in the changing sky for August 24 – September 1.

Last March 3rd, Europeans had a fine late-night view of the previous total lunar eclipse. In France, Laurent Laveder captured a series of images to make this composite. The August 28th eclipse, by contrast, will occur low in the west as dawn is brightening for many observers.

Laurent Laveder

Friday, August 24

Plan now to watch the eclipse of the Moon Tuesday morning, August 28th. Update Tuesday: It happened right on schedule (hey, we never get these things wrong); see our article.

The first-discovered asteroid, 1 Ceres (magnitude 8.7), is passing 0.4° south of Xi Tauri (magnitude 3.7) late tonight.

Saturday, August 25

Jupiter's smallest major moon, Europa, casts its very tiny black shadow onto Jupiter's face from 6:43 to 9:19 p.m. Eastern Daylight Time.

Sunday, August 26

Uranus, magnitude 5.7, is passing within 1/4° of the yellow-orange star Phi Aquarii, magnitude 4.2. They're well up in the southeast by 11 p.m. Uranus will remain within 1/2° of the star until September 5th. There's a bright Moon in the area tonight and for the next few nights, but even so, you should have little trouble if the air is good and clear.

Monday, August 27

Full Moon. A total eclipse of the Moon occurs before and/or during dawn tomorrow morning for much of the Americas. The farther west you are the better. (For Hawaii the eclipse happens during the middle of the night. For Australia, New Zealand, and much of the Far East the local time is Tuesday evening, perhaps around sunset.) See the August Sky & Telescope, page 50, or our article and timetable online.

Tuesday, August 28

Brilliant Vega shines overhead right after dark this week if you're at a mid-northern latitude. Vega passes exactly though your zenith if you live at latitude 39° N (Sacramento, Kansas City, Cincinnati, Washington DC).

Wednesday, August 29

The bright asteroid 4 Vesta, currently magnitude 7.2, is 0.4° north of dazzling Jupiter this evening. Cloudy? Vesta remains fairly near Jupiter for several days. See the finder chart in the September Sky & Telescope, page 58, or the one online.

Thursday, August 30

Whenever Vega is overhead, Arcturus, the other brightest star of summer, is lowering in the west. Look a third of the way up from Arcturus to Vega to spot the mostly dim constellation Corona Borealis, the Northern Crown — a little starry semicircle. Look two thirds of the way from Arcturus to Vega for the dim Keystone of Hercules.

Friday, August 31

Before dawn's first light Saturday morning, skygazers in the far western US will be under the stars watching for a possible outburst of the Aurigid meteors. See the September Sky & Telescope, page 56, or our version online.

Saturday, September 1

Look for the asteroid 2 Pallas (magnitude 8.8) passing 0.2° east of 34 Pegasi (magnitude 5.8) tonight.

Looking east-northeast around 1 a.m. daylight saving time

Mars and Aldebaran rise and shine together late these nights. The blue 10° scale is about the size of your fist held at arm's length.

Sky & Telescope diagram.

Want to become a better amateur astronomer? Learn your way around the constellations. They're the key to locating everything fainter and deeper to hunt with binoculars or a telescope. For an easy-to-use constellation guide covering the whole evening sky, use the big monthly foldout map in each issue of Sky & Telescope, the essential magazine of astronomy. Or download our free Getting Started in Astronomy booklet (which only has bimonthly maps).

Once you get a telescope, to put it to good use you'll need a detailed, large-scale sky atlas (set of maps; the standard is Sky Atlas 2000.0) and good deep-sky guidebooks (such as Sky Atlas 2000.0 Companion or the enchanting though somewhat dated Burnham's Celestial Handbook). Read here how to use them effectively.

More beginners' tips: "How to Start Right in Astronomy".

This Week's Planet Roundup

Mercury is deep in the glow of sunset.

Venus is emerging from the glow of sunrise, just beginning its grand apparition as the Morning Star for the next half-year. Look for it above the eastern horizon 60 to 40 minutes before sunrise. It's getting a little higher every day. (To find your local sunrise time, make sure you've put your location into our online almanac. If you're on daylight saving time like most of North America, make sure the Daylight Saving Time box is checked.)

By August 28th, surface features were again showing more normally through Mars's dusty atmosphere, as the past two months' worth of dust activity abated. Just to the right of the central meridian in this image is Sinus Meridiani, where Opportunity has resumed roving. North is up. Sean Walker took this stacked video image through color filters using a DMK 12AF04 camera on a 12.5-inch Newtonian reflector. The time was 8:14 UT August 28th. Mars was (and is) still only 8 arcseconds in diameter.

S&T: Sean Walker

Mars (magnitude +0.3, in Taurus) rises around midnight daylight saving time and shines very high in the southeast before dawn. It's near twinkly Aldebaran, which is similarly colored but not as bright. Look above them after they rise for the Pleiades; see the sky scene above.

In a telescope Mars is now 8 arcseconds in diameter, half the size it will be around its Christmas-season opposition.

Incidentally: if friends or family tell you they've read that Mars will become as big and bright as the full Moon this week, point them to our article about the regular-as-clockwork August Mars Hoax.

Jupiter (magnitude –2.2, in southern Ophiuchus) glares in the south-southwest during twilight and lower in the southwest after dark. Get your telescope on it as early as possible (though it has shrunk to a small-for-Jupiter diameter of 38 arcseconds). Antares, less bright, sparkles redly 5° below Jupiter; the two have been evening companions all summer. Other stars of Scorpius shine to their right and lower left.

Saturn remains hidden deep in the glow of sunrise.

Uranus, imaged at high power on August 28, 2007, with a 12.5-inch reflector using the stacked-video technique. Visually Uranus appears nowhere near this colorful: pale gray with only a hint of green-blue.

S&T: Sean Walker

Uranus (magnitude 5.7, in Aquarius) and Neptune (magnitude 7.8, in Capricornus) are well up in the southeast by late evening. This week Uranus fits in the same telescopic field of view with Phi Aquarii, magnitude 4.2.

Pluto (magnitude 13.9, in the northwestern corner of Sagittarius) is highest in the south-southwest as soon as it gets dark, about 18° east-northeast of Jupiter. Finder charts for Uranus, Neptune, and Pluto are in the July Sky & Telescope, page 60.

All descriptions that relate to your horizon — including the words up, down, right, and left — are written for the world's midnorthern latitudes. Descriptions that also depend on longitude (mainly Moon positions) are for North America. Eastern Daylight Time (EDT) equals Universal Time (UT, UTC, or GMT) minus 4 hours.

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