Sagittarius, the cosmic teapot
By PAUL DERRICK
Although this night sky region has nothing to do with current “tea party” politics, it does involve shameless deceit involving the two signature constellations of summer – Sagittarius and Scorpius.
You’re probably familiar with the story of the Trojan Horse in which the Greeks used a gift horse to entice the city of Troy to lower its defenses, making it vulnerable to a sneak attack.
Here the trickster is Sagittarius the Centaur-archer who disguises himself as a cosmic teapot in to entice his neighbors, Scorpius the Scorpion and Lupus the Wolf, into a deadly trap. Inviting them over for a neighborly cup of tea, he intends to shoot them with his bow and arrow when they get within range. Not only does he dislike having these guys for neighbors, the nearby Corona Australis the Southern Crown suggests this is also a territorial fracas to determine who rules this area of the sky.
The drama occurs far to the south with its players visible in the early evenings of summer. The story ends like another classic – the one about the lady or the tiger. We are left to wonder if the scorpion and wolf will be deceived by Sagittarius’ disguise, or perhaps they’ve also heard the Trojan Horse story.
Sagittarius looks more like a teapot than an archer, and Scorpius, with some imagination, does resemble a scorpion with his hooked tail to the lower left, pincers to the upper right, and the bright reddish star Antares as his head. Lupus, partly below the horizon, doesn’t look like much of anything, and Corona Australis is so faint and near the horizon as to be nearly unnoticeable.
The heart of the Milky Way galaxy runs through Scorpius and Sagittarius, making it one of the richest areas of the night sky, full of star clusters and nebulae. When viewed from beyond city lights, the brightest part of the Milky Way looks like steam arising from the spout of the Sagittarius’ teapot.
Night Sky Events
1 Wed.: Lammas, a cross-quarter day celebrating the middle of summer.
1 Wed.: The full Moon is called the Grain Moon and Green Corn Moon.
7 Tue. evening: Slow-moving Saturn, spending the entire month less than 5° above Virgo’s alpha star Spica, passes closest tonight.
9 Thu. morning: The Moon is at 3rd quarter.
10 Fri. morning: The waning gibbous Moon passes within 4° to the upper right of the Pleiades star cluster although its glare will rather overpower the lovely cluster.
11 Sat. morning: The Moon has now moved just above Jupiter, Aldebaran and the Hyades star cluster.
** 11 Sat. all night: The Perseid meteor shower peaks with no Moon interference until after midnight.
13 Mon. morning: The waning crescent Moon is 4° above Venus low in the east before dawn – and is 8° below the “morning star” the next morning.
** 13 Mon. evening: Spica (bottom), Mars (middle), and Saturn align low in the west southwest; they are nearly equal in brightness and will fit within the same field of view of most binoculars.
14 Tue. evening: Reddish Mars passes within 3° of creamy Saturn.
15 Wed. morning: Venus is at greatest elongation 46° west of the rising Sun.
15 Wed. morning: The thin waning crescent Moon is 8° to the upper right of Mercury low in the east as dawn begins to break.
16 Thu. morning: Mercury is at greatest elongation 19° from the rising Sun with an ever-thin crescent Moon to its lower right.
17 Fri.: The Moon is new.
18 Sat. morning: Mercury passes 2° to the right of the Beehive star cluster near the east northeastern horizon about an hour before sunset; binoculars will help with the lovely but faint star cluster.
** 21 Tue. early evening: The waxing crescent Moon, the star Spica (lower right), Saturn (upper right), and Mars (upper left) form a tight lumpy-jawed square very low in the west southwest at dusk; all four will be seen within the same field of view of most binoculars and should be pretty awesome.
24 Fri.: Neptune is at opposition – on the opposite side of Earth from the Sun.
24 Fri. evening: The Moon is at 1st quarter.
31 Fri.: The full Moon, being the second for the month, is called a Blue Moon although the name has nothing to do with its color.
Note: August and September are the best months to see the zodiacal light in the morning an hour before dawn begins to break; under very dark skies, look for a triangular-shaped cosmic cloudiness rising 30° or more from the eastern horizon.
The Sun, Moon and planets rise in the east and set in the west due to Earth’s west-to-east rotation on its axis.
Evenings: Mars, Saturn
Morning: Mercury, Venus, Jupiter
* Mercury starts the month in the glare of the rising Sun, quickly emerges low in the east, reaches it best by mid-month, and begins dipping back into the Sun’s glare by month’s end.
* Venus, the brilliant “morning star,” is at its highest above the rising Sun in latter August.
* Mars, low in the west southwest in the early evening, now sets before midnight.
* Jupiter, rising in the wee hours, is well up in the east by morning, and further above the much brighter Venus.
* Saturn, in the west southwest in the evening, sets before midnight early in the month and soon after sunset by month’s end; it is nearing the end of its 2012 evening appearance.
Perseid Meteor Shower
The Perseid meteor shower is predicted to peak in the early morning of Aug. 12, thus there might be increased meteor activity either or both of two nights – Aug. 11/12 and 12/13. The best viewing will likely be from dark until the Moon rises an hour or two after midnight. Meteors are best seen with naked eyes from less light-polluted rural areas. In a reclined position, slowly pan the entire sky while focusing attention on the darkest part which is usually overhead.
Total Solar Eclipse Early Notice: It is now only 5 years until Aug. 21, 2017, when a 70-mile wide shadow of a total solar eclipse passes across the middle of the U.S. from Oregon to South Carolina. Start making your travel plans.
Aug. 1 is the birthday of Maria Mitchell (1818-1889), America’s first woman astronomer.
Paul Derrick is an amateur astronomer who lives in Waco. His website www.stargazerpaul.com contains an archive of past Stargazer columns, a schedule of his upcoming programs, star parties and classes, and other basic stargazing information. Contact him at: email@example.com, or 254-723-6346.
Story filed under: Big Bend Blog