Some daily events in the changing sky for July 3 – 11.
Antares glitters just a few degrees left of the waxing gibbous Moon as seen from North America this evening, as shown at right. Seen from Hawaii, the Moon occults (covers) Antares around midnight (details).
Saturday, July 4
Sunday, July 5
Monday, July 6
Tuesday, July 7
Wednesday, July 8
Thursday, July 9
Friday, July 10
Saturday, July 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 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 and a curious mind." Without these, "the sky never becomes a friendly place."
More beginners' tips: "How to Start Right in Astronomy".
This Week's Planet Roundup
Mercury is hidden in the glow of dawn.
Venus and Mars (magnitudes –4.2 and +1.1, respectively) are due east during dawn. Venus is a dazzler; Mars, to Venus's upper right, is 130 times fainter. They're moving farther apart, from 5° to 7½° separation this week. Look below Venus for twinkly Aldebaran, similar to Mars in brightness.
Four reasons combine to create their great brightness disparity. Mars is farther from the Sun so it's illuminated less brightly than Venus; Mars is a smaller planet; its surface is darker and less reflective than Venus's white clouds; and Mars is currently farther from Earth.
Jupiter (magnitude –2.7, in Capricornus) rises around 10 or 11 p.m. daylight saving time and shines brightly in the south at dawn. The sharpest telescopic glimpses may come during morning twilight, when the atmospheric seeing sometimes turns very steady.
Saturn (magnitude +1.0, in Leo) glows in the west at dusk and sinks lower as evening advances. Look early! In a telescope Saturn's rings are narrowing, appearing only 3° from edge on. And see how they've dimmed. The caption at right tells why.
Uranus (magnitude 5.8, in Pisces), is high in the southeast before dawn.
Neptune (magnitude 7.9, in Capricornus) remains only 0.6° from Jupiter, but it's 17,000 times fainter. See our finder charts for Uranus and Neptune.
Pluto (14th magnitude, in northwestern Sagittarius) is at its highest in the south before midnight. See the finder chart in the June Sky & Telescope, page 53.
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 (also known as UT, UTC, or GMT) minus 4 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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