Some daily events in the changing sky for September 18 – 26.
Friday, Sept. 18
Saturday, Sept. 19
Sunday, Sept. 20
Monday, Sept. 21
Tuesday, Sept. 22
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. 23
Thursday, Sept. 24
Friday, Sept. 25
Saturday, Sept. 26
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 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 (they may not point quite where the computer tells them to). And 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 is hidden in the glare of the Sun.
Venus (magnitude –3.9, in Leo) shines low in the east before and during dawn. Look for Regulus, much fainter, just ½° from Venus on the morning of September 20th, then about 1° farther to Venus's upper right for each day thereafter.
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 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) comes into view in the southeast as twilight fades — the first "star" to appear after sunset. It's higher in better telescopic view by 9 or 10 p.m. The 4th-magnitude star less than ½° from Jupiter is Iota Capricorni.
Saturn is hidden behind the glare of the Sun.
Uranus (magnitude 5.7, just below the Circlet of Pisces) is well up in the southeast by 10 p.m.
Neptune (magnitude 7.8, in Capricornus) appears 6° east of Jupiter — and 16,000 times fainter. See our finder charts for Uranus and Neptune.
Pluto (14th magnitude, in northwestern Sagittarius) is still fairly well up in the south-southwest right after dark. See the finder chart in the June Sky & Telescope, page 53. 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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