Some daily events in the changing sky for September 25 October 3.
Friday, Sept. 25
Saturday, Sept. 26
Sunday, Sept. 27
Monday, Sept. 28
Tuesday, Sept. 29
For a complete list of such mutual events among Jupiter's satellites that are visible from North America through the end of the year, see the October Sky & Telescope, page 56.
Wednesday, Sept. 30
Thursday, Oct. 1
Friday, Oct. 2
Saturday, Oct. 3
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 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
Mercury barely emerges low in the sunrise by about September 29th. Look for it below Venus, as shown at right.
Venus (magnitude 3.9, in Leo) shines low in the east before and during dawn. Look for Regulus, much fainter, above it by a rapidly increasing amount each day.
Mars (magnitude +0.8, in Gemini near Pollux and Castor) rises around midnight or 1 a.m. and is very high in the east before dawn. In a telescope it's still only 6.5 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 arcseconds wide.
Jupiter (magnitude 2.7, in Capricornus) shines in the southeast as twilight fades the first "star" to appear after sunset. It's highest in the south by about 9 p.m.
Saturn follows Mercury up into dawn view by the end of the week. Use binoculars to look for it below Mercury after about September 29th, as shown here.
Uranus (magnitude 5.7, below the Circlet of Pisces) is well up in the southeast during evening. Also catch the 8th-magnitude asteroid 3 Juno in Uranus's vicinity.
Neptune (magnitude 7.8, in Capricornus) appears 6° or 7° east of Jupiter and 16,000 times fainter.
Pluto (14th magnitude, in northwestern Sagittarius) is getting lower in the southwest after dark. Use the finder chart in the June Sky & Telescope, page 53, before it's too late. Good luck.
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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