This Week’s Sky at a Glance

As twilight fades, use the waxing crescent Moon to locate Mars down below.

Friday, November 16

  • Spot the crescent Moon in the west as twilight fades, and use it to guide your way down to little Mars, as shown at right.

  • The Leonid meteor shower should be at its best in the hours before dawn Saturday morning. Under a dark sky you might see a dozen or so Leonids per hour. There is no moonlight.

    Saturday, November 17

  • With a small telescope, watch Jupiter's big moon Ganymede slowly disappear into eclipse by Jupiter's shadow around 11:30 p.m. EST; 8:30 p.m. PST. Find Ganymede just off Jupiter's western side.

  • At roughly the same time, Jupiter's Great Red Spot (actually pale orange-tan) appears nearest to the center of the planet's disk. For a listing of many more Jupiter events this month, good worldwide, see the November Sky & Telescope, pages 53-54.

    Sunday, November 18

  • A low-altitude challenge: If the sky is very clear as twilight fades, aim your scope at tiny little Mars from a site with a low southwestern view. Follow Mars down as night falls. Can you detect the Lagoon Nebula, M8, and its embedded star cluster 1/3° or so to Mars's right?

    Algol (Beta Persei) was the first eclipsing variable star ever discovered. Good comparison stars are Gamma (γ) Andromedae to Algol's west, magnitude 2.1, and Epsilon (ε) Persei to its east, magnitude 2.9. Click for larger view
  • Algol in Perseus, the prototype eclipsing binary star, should be in one of its periodic dimmings, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 10:45 p.m. EST. Algol takes several additional hours to fade and to rebrighten.

    Monday, November 19

  • Fomalhaut, the "Autumn Star," culminates (reaches its highest point due south) around 7 p.m. now, depending on how far east or west you live in your time zone. High above, the western side of the Great Square of Pegasus points almost down to it. The other side of the Great Square points down roughly to Beta Ceti (Diphda or Deneb Kaitos), not quite so far.

    Tuesday, November 20

  • First-quarter Moon (exact at 9:31 a.m.). The Moon shines high in the south in early evening, below the Water Jar of Aquarius.

    Wednesday, November 21

  • Algol is at minimum light again, for a couple hours centered on 7:34 p.m. EST. Algol takes several additional hours to rebrighten.

    Thursday, November 22

  • The Moon is under the Great Square of Pegasus as the stars come out.

  • Jupiter's moon Io disappears into eclipse by Jupiter's shadow, barely beyond the planet's western edge, at 11:20 p.m. EST (8:20 p.m. PST). Jupiter's Great Red Spot transits the planet's central meridian around 10:16 p.m. EST.

    Spot Venus at dawn this week, and keep an eye on much fainter Saturn and Spica moving in its background.

    Friday, November 23

  • Some pre-telescopic astronomy: Sometime between 6:30 and 8:30 this evening, depending on how far east or west you live in your time zone, bright Vega sinking in the northwest and bright Capella climbing in the northeast (well left of brighter Jupiter) will be at exactly the same height. How accurately can you time this event for your location? An astrolabe would help.

    Saturday, November 24

  • Look left of the Moon this evening, by a fist-width at arm's length or a little more, for the two or three brightest stars of Aries.


    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 guide to astronomy. Or download our free Getting Started in Astronomy booklet (which only has bimonthly maps).

    The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6 — which may sound like a lot, but that's less than one star in an entire telescopic field of view, on average. By comparison, Sky Atlas 2000.0 plots 81,312 stars to magnitude 8.5, typically one or two stars per telescopic field. Both atlases include many hundreds of deep-sky targets — galaxies, star clusters, and nebulae — to hunt among the stars.
    Sky & Telescope

    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 the little Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger and deeper Sky Atlas 2000.0 (stars to magnitude 8.5); and the even larger Uranometria 2000.0 (stars to magnitude 9.75). And read how to use sky charts with a telescope effectively.

    You'll also want a good deep-sky guidebook, such as Sue French's Deep-Sky Wonders collection (which includes its own charts), Sky Atlas 2000.0 Companion by Strong and Sinnott, the bigger Night Sky Observer's Guide by Kepple and Sanner, or the beloved if dated Burnham's Celestial Handbook.

    Can a computerized telescope replace charts? Not for beginners, I don't think, and certainly not on mounts and tripods that are less than top-quality mechanically (able to point with better than 0.2° repeatability). As Terence Dickinson and Alan Dyer say in their invaluable 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

    The Great Red Spot's side of Jupiter is busy indeed. On November 5th, when Christopher Go shot this superb image from his low latitude in the Philippines, the orange ring of Oval BA and the little dark-red dot following it had finished passing south of (above) the Great Red Spot. Huge turbulence roils the South Equatorial Belt behind the Great Red Spot.

    The South Temperate Belt is barely visible along some of its length but prominent elsewhere. Four white ovals dot the South South Temperate Belt. On the north (lower) side of the planet, the North Equatorial and North Temperate belts have become cleanly separated by the North Tropical Zone's return to whiteness. Blue festoons — apparently gaps between clouds — intrude into the bright Equatorial Zone north of the Great Red Spot.


    Mercury is hidden in the glare of the Sun.

    Venus (magnitude –3.9, in Virgo) rises in the east an hour before the first glimmer of dawn. By dawn it's shining brightly in the east-southeast, as shown above.

    Look for much-fainter Saturn lower left of Venus, and Spica to Venus's right or upper right.

    Mars (magnitude +1.2, in Sagittarius) remains low in the southwest in evening twilight. In a telescope it's just a tiny blob 4.4 arcseconds in diameter.

    Jupiter (magnitude –2.8, in Taurus) rises in the east-northeast in twilight, with Aldebaran to its right or lower right. Above them are the Pleiades. They all climb into fine view as evening advances.

    Saturn (magnitude +0.6, in Virgo) is lower left of bright Venus before and during dawn. They appear closer together every day. They're on their way to a conjunction less than 1° apart on the American mornings of November 26th and 27th.

    Uranus (magnitude 5.8, in Pisces) and Neptune (magnitude 7.9, in Aquarius) are conveniently placed in the south in early evening. Finder charts for Uranus and Neptune.


    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. Eastern Standard Time is UT minus 5 hours.


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