Some daily events in the changing sky for October 16 – 24.
Friday, October 16
Saturday, October 17
(For a complete list of such mutual events among Jupiter's satellites visible from North America through the end of the year, see the October Sky & Telescope, page 56.)
(The Red Spot transits about every 9 hours 56 minutes; for all of the Red Spot's central-meridian crossing times, good worldwide, use our Red Spot calculator or print out our list for the rest of 2009.)
Sunday, October 18
Monday, October 19
Tuesday, October 20
Wednesday, October 21
Thursday, October 22
Friday, October 23
Saturday, October 24
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 map in the center of 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 charts; the standards are Sky Atlas 2000.0 or the smaller Pocket Sky Atlas) and good deep-sky guidebooks (such as Sky Atlas 2000.0 Companion by Strong and Sinnott, the more detailed and descriptive Night Sky Observer's Guide by Kepple and Sanner, or the classic Burnham's Celestial Handbook). Read how to use them effectively.
Can a computerized telescope take their place? I don't think so — not for beginners, anyway (and especially not on mounts that are less than top-quality mechanically). As Terence Dickinson and Alan Dyer say in their 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 and a curious mind." Without these, "the sky never becomes a friendly place."
More beginners' tips: "How to Start Right in Astronomy".
This Week's Planet Roundup
Venus, Mercury, and Saturn are low in the east during dawn, changing configuration daily. Venus is by far the brightest. Mercury is barely above the horizon below Venus and may be gone from sight by week's end. Saturn just had a close conjunction with Venus (on October 13th) and now climbs higher to the bright planet's upper right. Look carefully; Saturn (magnitude +1.1) is only a hundredth as bright as Venus (magnitude –3.9). Binoculars help as dawn grows bright.
Mars (magnitude +0.6, in Cancer) rises around midnight and is very high in the southeast before dawn. It's below Gemini's head stars, Pollux and Castor. In a telescope Mars is still only 7.2 arcseconds wide: a tiny, fuzzy blob, though noticeably gibbous. Mars is on its way to an unremarkable opposition late next January, when it will be 14.1 arcseconds wide.
Jupiter (magnitude –2.6, in Capricornus) shines brightly in the south in early evening and lower in the southwest as night grows late. It sets around 1 or 2 a.m.
Uranus (magnitude 5.7, below the Circlet of Pisces) is well up in the southeast to south during evening.
Neptune (magnitude 7.9, in Capricornus) is about 7° east of Jupiter.
See our finder charts for Uranus and Neptune. For a guide to spotting the challenging satellites of Uranus and Neptune at any date and time (you'll need a big scope), see the October Sky & Telescope, page 59.
Pluto (14th magnitude, in Sagittarius) is sinking low in the southwest after dark.
All descriptions that relate to your horizon or zenith — 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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