Some daily events in the changing sky for February 1 – 9.

Comet Holmes is moving away from Algol, dimming and enlarging ever more. With the evening sky moonless this week, keep trying for it with binoculars — and if you have a very dark sky, your unaided eyes. When will you last be able to detect it? Even as Holmes (probably) fades to invisibility, it will remain in the evening sky through April; chart.

Friday, February 1

  • Venus and Jupiter were in conjunction this morning (0.6° apart), and they're still only 1.1° or 1.2° apart on Saturday morning as seen from North America (0.9° at the time of dawn in Europe). Look low in the southeast before sunrise, as shown at right.

    Looking southeast in early dawn

    As Venus and Jupiter start drawing apart, the thinning Moon passes by them. (These scenes are always drawn for the middle of North America, at latitude 40° north, longitude 90° west. European observers: move each Moon symbol a quarter of the way toward the one for the previous date. For clarity, the Moon is shown three times actual size.)

    Sky & Telescope diagram

    To find your local sunrise time, make sure you've put your location into our online almanac (and make sure the Daylight Saving Time box is unchecked).

  • The bright eclipsing variable star Algol should be in one of its periodic dimmings, magnitude 3.4 instead of its usual 2.1, for a couple hours this evening centered on 11:16 p.m. EST; 8:16 p.m. PST. Algol takes several additional hours to fade and to rebrighten. (For all times of Algol's minima this month, good worldwide, see the February Sky & Telescope, page 73.)

    Saturday, February 2

  • In early dawn Sunday morning, the waning crescent Moon hangs a fist-width at arm's length to the right of Venus and Jupiter, as shown above.

    Sunday, February 3

  • As Venus and Jupiter creep upward early in the brightening dawn Monday morning, look for the thin crescent Moon below them (as shown above).

    Monday, February 4

  • Algol should be at minimum light for a couple hours centered on 8:06 p.m. Eastern Standard Time.

    Tuesday, February 5

  • Mira, the brightest long-period variable star in the sky, should be at its peak brightness of about magnitude 3.4 this week. So it ought to be easy to spot with the unaided eye. Follow Mira's doings with the article and comparison-star chart on page 71 of the March Sky & Telescope.
  • Another red long-period variable star, U Orionis at the top of Orion's Club, should also be about at maximum this week. Though it's no match for Mira, U Ori is still one of the brightest long-period variables, typically peaking at around magnitude 6.3.

    Totally Eclipsed Moon

    A preview of the Moon on the 20th? The total lunar eclipse of March 3-4, 2007, was a relatively bright one. S&T editor Rick Fienberg captured this view from Garching, Germany, where he was attending a planning meeting for the International Year of Astronomy 2009. Click image for larger view.

    S&T: Rick Fienberg

    Wednesday, February 6

  • New Moon (exact at 10:44 p.m. EST). An annular eclipse of the Sun occurs over parts of Antarctica. The eclipse is partial in New Zealand and southeastern Australia, on Feb. 7th local date.

    Thursday, February 7

  • Algol should be at minimum light for a couple hours centered on 4:55 p.m. EST. This is before sunset even for the East Coast, but you can watch Algol rebrighten during the evening.

    Friday, February 8

  • February is when the Big Dog, Canis Major, prances highest in the south after dinnertime, showing off brilliant Sirius on his collar. With a telescope, you can hunt for more galaxies and clusters here than you probably ever knew. See Sue French's "Deep-Sky Wonders" column and chart in the February Sky & Telescope, page 74.

    Saturday, February 9

  • Start planning now for the grand total eclipse of the Moon that's coming on the evening of Wednesday, February 20th, for all of the Americas. Throw an eclipse party! See the February Sky & Telescope, page 68.

    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 foldout 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 maps; the standard is Sky Atlas 2000.0) and good deep-sky guidebooks (such as Sky Atlas 2000.0 Companion by Strong and Sinnott, the even more detailed Night Sky Observer's Guide by Kepple and Sanner, or the enchanting though increasingly dated Burnham's Celestial Handbook). Read how to use them effectively.

    More beginners' tips: "How to Start Right in Astronomy".

    This Week's Planet Roundup

    Mercury has disappeared into the Sun's glare.

    Venus and Jupiter (magnitudes –3.9 and –1.9, in Sagittarius) are the two "Morning Stars" low in the southeast during dawn. The brighter one is Venus. After their February 1st conjunction, Jupiter starts climbing away from Venus day by day. On Saturday morning, Feb. 2nd, they're still just 1.1° or 1.2° apart, but by the 9th they widen to 8° apart.

    Saturn, Titan, and Rhea on Jan 22, 2008

    Titan and Rhea, Saturn's two brightest satellites, stood north of the planet when S&T's Sean Walker took this image at 6:17 UT January 22nd through mediocre atmospheric seeing.

    S&T: Sean Walker

    Mars (about magnitude –0.4, in eastern Taurus) shines very high in the southeast to south during evening, high above Orion. The fairly bright star near it is Beta (β) Tauri, also known as El Nath, magnitude +1.6 and pale blue-white. In a telescope, Mars diminishes from 11.9 to 11.0 arcseconds in apparent diameter this week. See the telescopic observing guide and surface-feature map in the November Sky & Telescope, page 66, or the short version online.

    Saturn (magnitude +0.4, in Leo) rises in the east around 7 p.m. and is highest in the south after midnight. Fainter Regulus (magnitude +1.4) is 7° west of Saturn: to its upper right after they rise. Only a little dimmer than Regulus is Gamma (γ) Leonis (magnitude +2.1), located 8° to Regulus's north. The three make an eye-catching triangle.

    Uranus and Neptune are lost in the glow of dusk.

    Pluto (magnitude 14.0, in Serpens Cauda) is low in the southeast just before dawn.

    All descriptions that relate to your horizon or zenith — including the words up, down, right, and left — are written for the world's midnorthern latitudes. Descriptions that also depend on longitude (mainly Moon positions) are for North America. Eastern Standard Time (EST) equals Universal Time (UT, UTC, or GMT) minus 5 hours.

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    • About Alan MacRobert

    Alan M. MacRobert became an avid Sky & Telescope subscriber in 1966 at age 14, joined the editorial staff in 1982, and is now a senior contributing editor, semi-retired. He played a role in practically every part of the magazine and the company's other products for more than a generation, both on the amateur-observing side and the science-reporting side. In 1994 a book collection of his observing how-tos and telescopic sky tours was published as Star Hopping for Backyard Astronomers. He has produced This Week's Sky at a Glance online every week since 1989.

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