Some daily events in the changing sky for April 3 – 11.
Comet Yi-SWAN may not be much at magnitude 8½, but it's far north crossing the bright pattern of Cassiopeia this week. For now it's about equally high in the northwest just after dusk and in the northeast just before the first light of dawn. Choose your time to avoid moonlight if possible. (Full Moon is April 9th.) See our AstroAlert with positions for plotting on your star atlas.
Friday, April 3
Saturday, April 4
The Moon after dusk forms a straight, diagonal line with Regulus and Saturn at its lower left, as shown at right.
Sunday, April 5
Monday, April 6
Tuesday, April 7
Wednesday, April 8
Thursday, April 9
Friday, April 10
Saturday, April 11
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 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 charts; the standards are Sky Atlas 2000.0 or the smaller Pocket Sky Atlas) 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 classic Burnham's Celestial Handbook). Read how to use them effectively.
Can a computerized telescope take their place? 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 and a curious mind." Without these, they note, "the sky never becomes a friendly place."
More beginners' tips: "How to Start Right in Astronomy".
This Week's Planet Roundup
Mercury is emerging from the glow of sunset. By late this week, you should be able to spot it glimmering (at about magnitude –1.5) low above the western horizon 30 or 40 minutes after sunset.
Venus (magnitude –4.2) is low in the dawn. Look for it above the eastern horizon about 20 or 30 minutes before sunrise. Don't confuse it with Jupiter higher and far to the right in the southeast. (You can find your local sunrise time from our online almanac. If you're on daylight saving time like most of North America, make sure the Daylight Saving Time box is checked). In a telescope, Venus is a slim crescent.
Mars (magnitude +1.2) is both dim and very low in the sunrise glow. Using big binoculars, you can try looking for it well to the right of Venus about 30 minutes before sunrise. Good luck.
Jupiter (magnitude –2.1, in Capricornus) shines low in the southeast during early dawn.
Saturn (magnitude +0.6, near the hind foot of Leo) shines in the southeast at dusk. It's highest in the south around 10 or 11 p.m. Look for Regulus 16° (roughly one and a half fist-widths at arm's length) to Saturn's upper right in early evening, and more directly to its right later at night.
In a telescope, Saturn's rings are 3½° from edge on. The rings will open to a maximum of 4° in May, then will close to exactly edge-on next September 4th — when, unfortunately, Saturn will be out of sight practically in conjunction with the Sun.
Uranus (6th magnitude) is hidden low in the sunrise glow, in the background of Venus and Mars.
Neptune (8th magnitude) is also hidden in the glow of dawn, in the background of Jupiter.
Pluto (14th magnitude, in northwestern Sagittarius) is located in the southeast before the first light of dawn.
All descriptions that relate to your horizon or zenith — 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 (known as UT, UTC, or GMT) minus 4 hours.
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