Some daily events in the changing sky for March 12 – 20.
Friday, March 12
And you probably know that if you follow the curve of the Dipper's handle out and around by a little more than a Dipper length, you'll arc to Arcturus (now rising in the east).
But did you know that if you follow the Pointers backward the opposite way, you'll land in Leo?
Draw a line diagonally across the bowl from where the handle is attached, continue on, and you'll go to Gemini.
And look at the two stars forming the open top of the Dipper's bowl. Follow this line past the bowl's lip far across the sky, and you crash into Capella.
Saturday, March 13
Sunday, March 14
Monday, March 15
Tuesday, March 16
Wednesday, March 17
Thursday, March 18
Friday, March 19
For instance, in Boston this evening, the Belt should be perfectly horizontal around 8:20 p.m. How accurately can you time this event at your location? Orion's Belt is slightly curved, so judge by the two stars on its ends. Can you rig up a sighting reference to make your measurement more precise, and track the time's day-to-day change? Welcome to pre-telescopic astronomy.
Saturday, March 20
David Dunham of the International Occultation Timing Association writes:
"Our last Pleiades passage in the USA until 2023 will occur Saturday evening, with the crescent Moon, about 25% sunlit, moving over the southern and eastern part of the cluster but missing all of the bright stars (except for Merope in the Corpus Christi, Texas area). But several 8th to 6th magnitude stars will be occulted, and one 5th-mag. star. Predictions of these (and of other total lunar occultations for all of 2010 for stars to mag. 6.0) for 40 of the larger North American cities can be downloaded in .zip files from Bob Sandy's website. There are some regional sites with predictions of fainter stars, for example for stars to 8th mag. in the Mid-Atlantic region (computed for near Washington, DC) at the bottom of my Mid-Atlantic occultation and expedition page."
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'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 more detailed and descriptive 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? 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 hidden in the glare of the Sun.
Venus (magnitude –3.9) is slowly emerging from the sunset. Look for it very low due west about 40 minutes after sundown.
Mars, now faded to magnitude –0.2, shines very high in the southeast at dusk and toward the south by 8 or 9 p.m. It's in Cancer, below Pollux and Castor at nightfall and left of them later in the evening.
In a telescope Mars is gibbous and shrinking: from 10.9 to 10.3 arcseconds in diameter this week. The north polar cap remains its most visible marking. Identify other surface features using the Mars map and observing guide in the December Sky & Telescope, page 57.
Jupiter is hidden deep in the glow of sunrise.
Saturn (magnitude +0.5, in western Virgo) is nearly at opposition, which comes on the night of March 21st. Saturn glows low in the east at nightfall, higher in the southeast late in the evening, and highest in the south around 1 or 2 a.m. daylight saving time. In a telescope, Saturn's rings are tilted only 3.4° from edge-on. They'll narrow further to 1.7° in May.
Uranus and Neptune are hidden in the glare of the Sun.
Pluto (magnitude 14, in northwestern Sagittarius) is up in the southeast before 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 Standard Time (EST) equals Universal Time (also known as UT, UTC, or GMT) minus 5 hours.
"Science is built up of facts, as a house is with stones. But a collection of facts is no more a science than a heap of stones is a house."
— Henri Poincaré (1854–1912)
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