Friday, October 25
Saturday, October 26
By dawn on Sunday they're all high in the southeast to south, with Procyon now on the bottom and Regulus and Mars off to their lower left.
Sunday, October 27
Tuesday, October 29
Wednesday, October 30
Thursday, October 31
Friday, November 1
Want to become a better astronomer? Learn your way around the constellations. They're the key to locating everything fainter and deeper to hunt with binoculars or a telescope.
This is an outdoor nature hobby. For an easy-to-use constellation guide covering the whole evening sky, use the big monthly map in the center of each issue of Sky & Telescope, the essential guide to 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 charts). The standards are the little Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger and deeper Sky Atlas 2000.0 (stars to magnitude 8.5); and once you know your way around, the even larger Uranometria 2000.0 (stars to magnitude 9.75). And read how to use sky charts with a telescope.
You'll also want a good deep-sky guidebook, such as Sue French's Deep-Sky Wonders collection (which includes its own charts), Sky Atlas 2000.0 Companion by Strong and Sinnott, the bigger Night Sky Observer's Guide by Kepple and Sanner, or the beloved if dated Burnham's Celestial Handbook.
Can a computerized telescope replace charts? Not for beginners, I don't think, and not on mounts and tripods that are less than top-quality mechanically (able to point with better than 0.2° repeatability, which means heavy and expensive). As Terence Dickinson and Alan Dyer say in their invaluable Backyard Astronomer's Guide, "A full appreciation of the universe cannot come without developing the skills to find things in the sky and understanding how the sky works. This knowledge comes only by spending time under the stars with star maps in hand."
This Week's Planet RoundupMercury and Saturn are lost in the sunset.
Venus (magnitude –4.5) shines brightly in the southwest during dusk. It sets nearly an hour after dark now.
In a telescope Venus appears very close to half-lit. When will it — or did it — it appear exactly so? Visually, the dichotomy of Venus comes about a week or ten days before Venus wanes to be geometrically half-lit, which happens on October 30th. We see this offset timing because of the dim lighting at Venus's terminator combined with fuzzy seeing in a telescope and a (usually) bright-sky background.
Mars (magnitude 1.5) rises around 2 or 3 a.m. near Regulus (magnitude 1.4) in Leo. By dawn they're high in the east. Mars and Regulus are moving farther apart now, from a separation of 6° on October 26 to 11° on November 2nd. In a telescope Mars is just a tiny blob 5 arcseconds wide.
Comet ISON is below Mars, in the hind feet of Leo, before the first light of dawn, still a telescopic target at 9th or 10th magnitude. Use the finder chart for it in the November Sky & Telescope, page 50. Check for news at skypub.com/ISON.
Jupiter (magnitude –2.2, in Gemini) rises in the east-northeast around 10 or 11 p.m. and blazes high in the south by early dawn. About 8° left of it after it rises are Castor and Pollux. In a telescope Jupiter has grown to 41 arcseconds wide, as it heads toward its January 5th opposition. Its Great Red Spot has turned an unusually strong shade of orange.
Uranus (magnitude 5.7, in Pisces) and Neptune (magnitude 7.9, in Aquarius) are high in the southeast and south, respectively, by 8 or 9 p.m. Finder charts for Uranus and Neptune. See also the October Sky & Telescope, page 50.
All descriptions that relate to your horizon including the words up, down, right, and left are written for the world's mid-northern latitudes. Descriptions that also depend on longitude (mainly Moon positions) are for North America. Eastern Daylight Time (EDT) equals Universal Time (also known as UT, UTC, or GMT) minus 4 hours.
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