Sky at a Glance | April 27th, 2007

Some daily events in the changing sky for April 27 – May 5.

Looking west at dusk
Watch Venus pass between Beta and Zeta Tauri, the horns of Taurus, in the western sky at dusk this week.
Sky & Telescope diagram.

Friday, April 27

  • A dawn challenge: Uranus appears less than 1° south of Mars on Saturday and Sunday mornings. On Saturday morning (for the Americas), 1st-magnitude Mars, the 4.4-magnitude star Phi Aquarii, and 6th-magnitude Uranus form a little line 0.9° long, in that order from right to left. On Sunday morning, Mars is below the two faint dots.

    Try looking with binoculars or a telescope about 75 minutes before sunrise, depending on the clarity of the air. To find your local sunrise time, make sure you've put your location and current time zone into our online almanac.

    Saturday, April 28

  • Look for Spica this evening about two fist-widths at arm's length lower left of the Moon. About the same distance directly below the Moon, look for the four-star, sail-shaped constellation of Corvus, the Crow.

    Sunday, April 29

  • Venus is passing 3° south (lower left) of Beta Tauri this evening and tomorrow evening.

    Monday, April 30

  • Look for Spica shining above the Moon tonight. Far to their upper left shines brighter Arcturus.

    Tuesday, May 1

  • Full Moon tonight (exact at 6:09 a.m. Wednesday morning EDT).

    Wednesday, May 2

  • Now that it's May, can you still catch the Belt of Orion on its way out for the season? As twilight fades, look for it near the horizon far to the lower left of bright Venus. The Belt is nearly horizontal. Above it stands orange-red Betelgeuse, the last of Orion's bright stars to go.

    Thursday, May 3

  • Close to 3rd-magnitude Gamma Bootis lies the red long-period variable star V Bootis, which should be just past maximum light (8th magnitude) this week. See the article and chart in the May Sky & Telescope, page 62, and take a look with binoculars! After you've found V Boo once or twice, you can check in on it at a glance whenever you take binoculars out on a clear night.

    Friday, May 4

  • The waning gibbous Moon shines near Jupiter and Antares from about midnight tonight to dawn Saturday morning. See the dawn view below.

  • The annual Eta Aquarid meteor shower peaks before dawn Saturday morning; it's observable from the tropics and the Southern Hemisphere. But even there this isn't a good year for the Eta Aquarids, what with the bright moonlight.

    Saturday, May 5

  • As the evening grows late, bright Vega climbs well up in the northeast. Meanwhile bright Arcturus is shining very high in the southeast. Look a third of the way from Vega to Arcturus for the dim Keystone of Hercules. Look two thirds of the way for the dim semicircle of Corona Borealis, the Northern Crown.

    Looking away from the sunrise glow befiore dawn
    The Moon passes Antares and Jupiter in the morning sky as it wanes after full. (These scenes are 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. The blue 10° scale is about the size of your fist held at arm's length. For clarity, the Moon is shown three times 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 or the enchanting though dated Burnham's Celestial Handbook). Read here how to use them most effectively.

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

    This Week's Planet Roundup

    Mercury is hidden in the glare of the Sun.

    Venus in ultraviolet, April 20, 2007
    The clouds of Venus are essentially featureless to the eye, but they get more interesting in the ultraviolet. Sky & Telescope's Sean Walker took these stacked video images with a 12.5-inch reflector in excellent seeing before sunset on April 20, 2007. "Here are my two best results," he writes, taken 28 minutes apart. "I picked up a fused silica lens that I fashioned into a barlow — it has excellent UV transmission, though I still needed to add my Astro-Physics Barcon to achieve an acceptable image scale. Still, both together allowed a bright image at 98 frames per second."
    S&T: Sean Walker

    Venus (magnitude –4.1, in Taurus) is the brilliant "Evening Star" in the west during and after twilight. A few degrees to Venus's right, watch the not-quite-first-magnitude star Beta Tauri moving downward day by day.

    Mars (magnitude +1.0, in Aquarius) still remains low in the east-southeast during dawn.

    Jupiter (magnitude –2.5, in southern Ophiuchus) rises around 11 p.m. daylight saving time and dominates the south before dawn. Antares, less bright, sparkles 10° to Jupiter's upper right when they rise, and to its lower right by daybreak. There's a lot doing on Jupiter this season; see article. The clearest telescopic views are before and during dawn, when Jupiter is highest.

    Saturn on April 20, 2007
    Spica (left) and the constellation Corvus (right) shine below the Moon on the evening of April 28th.
    S&T: Sean Walker

    Saturn (magnitude +0.4, at the Leo-Cancer border) shines high in the southwest during evening. Regulus, less bright at magnitude +1.4, is 12° to its left or upper left. North of Regulus is 2.3-magnitude Algieba (Gamma Leonis), a fine telescopic double star.

    Uranus (magnitude 6, in Aquarius) is very low in the east-southeast before dawn, in the background of Mars.

    Neptune (magnitude 8, in Capricornus) low in the southeast before dawn.

    Pluto (magnitude 14, in northwestern Sagittarius) is not far from Jupiter in the south before dawn.

    All descriptions that relate to your horizon — 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 Daylight Time (EDT) equals Universal Time (UT, UTC, or GMT) minus 4 hours.

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