Friday, April 26
Saturday, April 27
Sunday, April 28
Monday, April 29
Tuesday, April 30
Wednesday, May 1
Thursday, May 2
Friday, May 3
Saturday, May 4
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).
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.
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 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
Mercury is lost in the glow of dawn.
Venus (magnitude –3.9) is just beginning an evening apparition that will continue for the rest of the year. How soon can you first pick it up? Use binoculars to look for Venus a mere 15 or 20 minutes after sunset, barely above the west-northwest horizon. It's far to the lower right of Jupiter for viewers at mid-northern latitudes.
Mars remains hidden in the glare of the Sun. Not until summer will it emerge in the dawn.
Jupiter (magnitude 2.0, in Taurus) is the first "star" to come out in the west after sunset, a little lower every day. It descends in the evening and sets around 10 or 11 p.m. Below Jupiter twinkles orange Aldebaran, and a similar distance above Jupiter is El Nath (Beta Tauri). Bright Capella shines to the upper right from there. In a telescope, Jupiter has shrunk to a disappointing 34 arcseconds wide.
Saturn (magnitude +0.1, in Libra) is at opposition Saturday night April 27th. All week it glows low in the east-southeast as twilight fades (to the lower left of Spica and farther lower right of Arcturus). It rises it higher all evening and shines highest in the south in the middle of the night.
Carefully note the brightness of the rings with respect to the globe. The rings always brighten for several days around opposition due to the Seeliger effect. The solid, very irregular particles of the rings preferentially reflect sunlight back in the direction it came from more than Saturn's cloudtops do. Watch as the rings dim back down later in the week, as Saturn moves away from the opposition point in Earth's sky.
Uranus is hidden in the dawn.
Neptune (magnitude 7.9, in Aquarius) is low in the east-southeast just before dawn.
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.
Like This Week's Sky at a Glance? Watch our SkyWeek TV short. It's also playing on PBS!
To be sure to get the current Sky at a Glance, bookmark this URL:
If pictures fail to load, refresh the page. If they still fail to load, change the 1 at the end of the URL to any other character and try again.