Periodic Comet Hartley 2 is about 7th magnitude, visible in binoculars in a dark sky. It's excellently placed very high these moonless evenings, passing just south of Cassiopeia as shown at right. But it's large and diffuse, meaning its light is spread out over a wide area (as seen in binoculars) — so you'll need an unpolluted dark sky. Binocular observers have been calling it easy from rural areas and invisible from suburbs.
Friday, October 1
Saturday, Oct. 2
Sunday, October 3
Monday, October 4
Tuesday, October 5
Wednesday, October 6
Thursday, October 7
Friday, October 8
Saturday, October 9
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 must have a detailed, large-scale sky atlas (set of charts). The standards are the Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger Sky Atlas 2000.0 (stars to magnitude 8.5); and the even larger and deeper Uranometria 2000.0 (stars to magnitude 9.75). And read how to use your charts effectively.
You'll also want a good deep-sky guidebook, such as Sky Atlas 2000.0 Companion by Strong and Sinnott, or the more detailed and descriptive Night Sky Observer's Guide by Kepple and Sanner, or the classic if dated Burnham's Celestial Handbook.
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."
This Week's Planet Roundup
Mercury (magnitude –1.2) drops back down into the sunrise this week. Early in the week, look for it low due east about 30 or 40 minutes before your time of sunrise.
Venus, though bright at magnitude –4.7, is disappearing very low in the southwest during bright evening twilight. It sets well before dark.
In a telescope Venus is becoming an ever thinner, longer crescent. The best telescopic views are had in daylight long before sunset — but don't accidentally sweep up the Sun! In mid- to late afternoon, place your scope in the shadow of a building or other obstacle where you have a clear view of the sky 30° to 35° to the Sun's left.
Mars, vastly dimmer at magnitude +1.5, is 7° above or upper right of Venus in bright twilight. That's about one field-of-view width in typical binoculars. You'll need them. Good luck.
Jupiter (magnitude –2.9, at the Pisces-Aquarius border) is two weeks past opposition. As twilight fades, Jupiter becomes very obvious low in the east-southeast. It shines high in the southeast by mid-evening, by far the brightest starlike point in the sky. It's highest in the south around midnight daylight saving time.
Jupiter is having an unusually close apparition; it continues to appear 49 arcseconds wide through mid-October. (In fact this opposition was closer than any other of Jupiter from 1963 to 2022, though only 1% or 2% closer than in any year when opposition occurs from mid-August through October, including last year and next. See article.)
Jupiter's Great Red Spot is near System II longitude 157°. Assuming it stays there, here's a list to print out of all the Great Red Spot's predicted transit times (times and dates in UT) for the rest of this observing season.
Saturn is hidden behind the glare of the Sun.
Uranus (magnitude 5.7) is 1½° to 2° east of Jupiter this week.
Neptune (magnitude 7.8, at the Aquarius-Capricornus border) is well placed earlier in the evening. See our finder charts for Uranus and Neptune online or in the September Sky & Telescope, page 56. Can you see any color in Uranus and/or Neptune?
Pluto (magnitude 14.0, in northwestern Sagittarius) is still fairly high in the south-southwest right after dark, and the evening sky is free of moonlight this week. Use the large finder chart in the July Sky & Telescope, page 60.
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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