Some daily events in the changing sky for October 9 17.
Friday, October 9
Saturday, October 10
Sunday, October 11
Monday, October 12
Tuesday, October 13
Wednesday, October 14
Thursday, October 15
Friday, October 16
Saturday, October 17
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 sinking lower to the horizon below it. Saturn just had a close conjunction with Mercury on October 8th and a close conjunction with Venus on October 13th.
Mercury is magnitude 0.9 but becoming more dimmed by atmospheric extinction. Saturn is a forlorn magnitude +1.1. Venus shines 100 times brighter than Saturn at magnitude 3.9. Bring binoculars! And see our article about this dawn planet dance.
Best viewing may be about 50 minutes before your local sunrise time. And when exactly is that? You can always find your sunrise and sunset times (and much else) once you 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.)
Mars (magnitude +0.7) rises around midnight and is very high in the southeast before dawn. It's near Gemini's head stars, Pollux and Castor. In a telescope Mars is still only 7 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 2.6, in Capricornus) shines brightly in the south-southeast as twilight fades it's the first "star" to appear after sunset. Jupiter is in quadrature (90° east of the Sun) on October 6th, so all month it displays its greatest difference in lighting between its east and west sides: not dramatic in a telescope, but noticeable.
Uranus (magnitude 5.7, below the Circlet of Pisces) is well up in the southeast during evening.
Neptune (magnitude 7.8) is in Capricornus 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 fairly big scope), see the October Sky & Telescope, page 59. October 10th marks the 163rd anniversary of William Lassell's discovery of Neptune's big moon Triton.
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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