This Week's Sky at a Glance
Some daily events in the changing sky for August 26 September 3
Supernova in M101. A supernova for backyard telescopes continues brightening in M101, the Pinwheel Galaxy off the Big Dipper's handle. Supernova 2011fe was discovered at magnitude 17.2 on August 24th, reached 13.8 on the 25th, and 12.5 on the 27th. On the American evening of the 29th (August 30.1 UT) I estimated it at magnitude 11.5 using a 12.5-inch scope at 75× and an AAVSO comparison-star chart. It was more readily visible than the galaxy itself in my moderately light-polluted suburban sky. Then on the evening of the 30th Tony Flanders put it at 11.2. On the evening of the 31st it was about 10.8. No sign of stopping yet!
The supernova should top out at about magnitude 10.6 if it's a standard Type Ia, as seems to be the case. See our article, Supernova Erupts in Pinwheel Galaxy. Plan to observe soon after dark while the Dipper's handle is still high.
Friday, Aug. 26
Saturday, Aug. 27
Sunday, Aug. 28
Monday, Aug. 29
Tuesday, Aug. 30
Wednesday, Aug. 31
Thursday, Sept. 1
Friday, Sept. 2
Saturday, Sept. 3
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 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 must have a detailed, large-scale sky atlas (set of charts). The standards are the Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger Sky Atlas 2000.0 (stars to magnitude 8.5); and the even larger and deeper Uranometria 2000.0 (stars to magnitude 9.75). And read how to use sky charts effectively.
You'll also want a good deep-sky guidebook, such as Sky Atlas 2000.0 Companion by Strong and Sinnott, or the more detailed and descriptive Night Sky Observer's Guide by Kepple and Sanner, or the classic if dated Burnham's Celestial Handbook.
Can a computerized telescope take their place? I don't think so not for beginners, anyway, and especially not on mounts that are less than top-quality mechanically. 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."
This Week's Planet Roundup
Mercury is emerging into view low in the dawn, brightening day by day. Look for it low in the east about an hour before sunrise; the later in the week the better. It's far down below Mars, Castor, and Pollux.
Venus is hidden in the glare of the Sun.
Mars (magnitude +1.4, crossing Gemini) rises around 2 a.m. daylight-saving time. By the beginning of dawn it's in good view well up in the east, to the right of Castor and Pollux. In a telescope, Mars is just a tiny blob only 4.7 arcseconds in diameter.
Jupiter (magnitude 2.6, in southern Aries) rises in the east-northeast around 10 p.m. daylight saving time. Look above it for the little star pattern of Aries and (once Jupiter is well up) closer below it for the head of Cetus, rather dim. Jupiter shines highest in the south just before dawn, making this the best time to examine it with a telescope. It's 44 arcseconds wide.
Saturn (magnitude +0.9, in Virgo) sinks down to the western horizon during twilight. Look for it far below high, bright Arcturus. Binoculars help. Left of Saturn by 10° twinkles Spica.
Uranus (magnitude 5.8, in western Pisces) and Neptune (magnitude 7.8, in western Aquarius) are well up in the south and southeast before midnight. Use our printable finder chart for both.
Pluto (magnitude 14.0, in northern Sagittarius) is still in the south-southwest right after dark; don't delay. A big finder chart for it is in the July Sky & Telescope, page 64.
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.
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