Sky at a Glance | February 15th, 2008

Some daily events in the changing sky for February 15 – 23.

Facing southeast and looking very high after dinnertime
The waxing Moon shines near Mars and especially Beta (β) Tauri on the evening of the 15th, while Capella looks on. This view is drawn for the middle of North America. European observers: move each Moon symbol a quarter of the way toward the one for the previous date.
Sky & Telescope diagram

Friday, February 15

  • Shining near the Moon this evening are Mars, pale yellow-orange, and Beta Tauri, pale blue-white, as shown here.

    Saturday, February 16

  • Around 9 p.m. at this time of year (depending on how far east or west you live in your time zone), the Big Dipper stands as high in the northeast as Cassiopeia does in the northwest. Both are upright: The Dipper is standing on its handle, and the flattened-W shape of Cassiopeia is standing on one end.

    Sunday, February 17

  • The Moon shines just to the right of Pollux and Castor this evening.

    Monday, February 18

  • A small telescope will always show Titan, Saturn's largest moon. Tonight and tomorrow night Titan is four ring-lengths to Saturn's east. A 6-inch scope will begin to show the orange color of its atmospheric haze. A guide to identifying all six of Saturn's satellites visible in amateur scopes is in the February Sky & Telescope, page 62.

    Tuesday, February 19

  • Look far underneath the bright Moon for Regulus and Saturn, as shown two pictures below.

    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 20

  • Total eclipse of the full Moon this evening for the Americas, and on Thursday morning for Europe and West Africa. See our online article with timetable, and full coverage in the February Sky & Telescope, page 68. Adding to the beaury of the scene, Saturn and Regulus stand more or less on either side of the Moon, as shown below.

    And take advantage of the dark sky during the total eclipse to have a look for Comet Holmes, very big but very dim, as described at the bottom of this page.

    Thursday, February 21

  • 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 centered on 1:02 a.m. Friday morning EST (10:02 p.m. Thursday evening 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.)

    At any random time you glance up at Algol, you have a 1-in-30 chance of catching it at least 1 magnitude fainter than normal.

  • The red long-period variable star S Canis Minoris is nearing its peak brightness (7th or 8th magnitude) this week.

    Friday, February 22

  • High overhead these evenings, notice how similar the pairing of Mars and Beta Tauri looks to the pairing of Pollux and Castor farther east. Even their colors are similar: orange and blue-white in both cases. Compare also the pairing of Procyon and Beta Canis Minoris lower down.

    Saturday, February 23

  • Saturn is at opposition tonight, opposite the Sun in our sky. This means it rises around sunset, is highest in the south around midnight, and sets around sunrise.

    Looking east around 8 p.m.
    The full Moon on the evening of the 20th — shown here when not in eclipse! — shines near Saturn and Regulus. This uneclipsed view is drawn for eastern North America. (European observers: to get your early-evening view, move each Moon symbol a quarter of the way toward the one for the previous date.) For clarity, the Moon is drawn three times its actual size.
    Sky & Telescope diagram

    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

    That's Venus?! Yep — as seen on February 7th in ultraviolet light, and with a lot of contrast enhancement. Although in white light Venus is featureless, classical visual observers long claimed to see very subtle marks on it from time to time, especially through a violet filter. Going even farther up the spectrum makes them plain.
    S&T: Sean Walker
    Mercury is emerging from deep in the glow of sunrise. Late in the week, use binoculars to look for it a little left of bright Venus.

    Venus (magnitude –3.9, moving from Sagittarius into Capricornus) is getting lower every morning. Look for it above the southeast horizon about 30 or 40 minutes before sunrise, well to the lower left of Jupiter.

    Mars (about magnitude –0.1, in eastern Taurus) shines very high in the south during evening, high above Orion. The fairly bright star near it is Beta (β) Tauri, or El Nath, magnitude +1.6 and pale blue-white. In a telescope, Mars dwindles from 10.4 to 9.6 arcseconds in apparent diameter this week. See the observing guide and surface-feature map in the November Sky & Telescope, page 66, or the short version online.

    Mars on Feb. 4, 2008
    Shooting from the Winter Star Party with Don Parker's 10-inch Takahashi Mewlon 250 DK scope, Sean Walker recorded Mars's north polar cap (top) in clear view now that the the north polar cloud hood is gone. Notice south polar clouds beginning to form. Syrtis Major is just left of the central meridian. The time was 4:44 UT February 4, 2008.
    S&T: Sean Walker

    Jupiter (magnitude –2.0, in Sagittarius) shines low in the southeast before and during dawn. It's moving ever farther to the upper right of Venus.

    Saturn (magnitude +0.3, in Leo) comes to opposition on the night of the 23rd. It glows low in the east as twilight fades, rises higher all evening, and stands highest in the south around midnight. Fainter Regulus (magnitude +1.4) is 6° 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.

    In a telescope, watch this week for the Seeliger effect, a brightening of Saturn's rings for several days around oppposition. The reason for this? The ice particles making up the rings "backscatter" sunlight (reflect it back the way it came) more efficiently than the material in Saturn's cloud tops. When Saturn is at opposition, Earth is in the line of backscattering. A daily series of images will show this particularly well.

    Uranus and Neptune are hidden in the glare of the Sun.

    Pluto (magnitude 14.0, in Sagittarius) is low in the southeast before the first light of dawn.

    Comet Holmes, evening of Feb. 11, 2008
    "Here's the latest in my continuing saga of photographing Comet Holmes with the TV-NP127is (5-inch) telescope and Apogee Alta camera," writes S&T's Dennis di Cicco. "This shot is from Monday evening in the cold and high wind. Exposures were 40 minutes blue, 40 minutes green, and 50 minutes red. The field here is almost exactly 3° wide, with north up. This comet is getting huge! So much so that I initially had a difficult time seeing it in a short exposure because it looked like the typical 'hot spot' in the center of the frame due to optical vignetting." Click image for larger view.
    S&T: Dennis di Cicco
    Comet Holmes continues to grow ever bigger and dimmer. At the Winter Star Party in the dark Florida Keys, says Sean Walker, "Comet Holmes was still naked eye, but only just — it was an averted-vision object as of February 7th. Ghostly through 8x50 binoculars." On February 11th through suburban light pollution, Dennis di Cicco could not see it with the naked eye at all when he took the picture at right. The comet is between the feet of Perseus; chart.

    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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