SKY REPORTER: August 2012
by Steve Beyer on
Wednesday August first, sunrise is at 5:53 a.m. Eastern Daylight Time. That evening the Sun, located in the constellation of the Crab, sets at 8:11 p.m.
Wednesday August 15 sunrise is at 6:06 a.m. and sunset occurs that day at 7:53 p.m.
The last day of this month, Friday the 31st the Sun is in Leo rising at 6:22 a.m. and setting at 7:29 that evening. During August the length of time the Sun is above the horizon each day decreases by one hour and 11 minutes. The altitude of the Sun at solar noon, its maximum daily elevation, descends during August from 67 degrees of arc on the first to 57 1/2 degrees on the 31st. Lower solar altitudes provide less concentrated Sunlight and shorter daily durations of daylight.
This month average overnight temperatures recorded in Central Park drop from 69 degrees Fahrenheit on the first to 66 degrees on the last day of August.
Principal Phases of the Moon are:
|Full Moon||August 1|
|Last Quarter||August 9|
|New Moon||August 17|
|First Quarter||August 24|
|Full Moon (“Blue Moon”)||August 31|
At the end of civil twilight Wednesday August 1 Mars and Saturn are both above the southwestern horizon in the constellation Virgo. Mars sets at 10:52 p.m. and Saturn sets that evening at 11:22. Other planets in our sky at the start of this month are Neptune in Aquarius, rising at 9:06 p.m.; Uranus rising at 10:31 in Cetus; Jupiter in Taurus rises at 1:25 a.m., on morning of August 2 followed by Venus, also in Taurus at 2:38; and Mercury in the Crab rising in bright twilight at 5:31 a.m.
The Full Moon of August first is located in the constellation Aquarius, near the border with Capricornus. On the last night of the month, we have our second Full Moon of August, a so-called “Blue Moon”. This provides several options, as traditional names for August’s Full Moon include Full Sturgeon Moon, Full Red Moon, and Full Grain Moon. With two Full Moons this month, two of these names might be used.
Mars is a center of attention due to Martian Rover Curiosity’s arrival at Gale Crater Monday August 6 at 1:31 a.m. ET. That morning the spacecraft containing its Mars Science Laboratory is scheduled to set down on the Red Planet via a sophisticated “Sky Crane” procedure.
NASA offers several ways to share the experience.
At New York City, Mars sets at 10:42 p.m. the evening before Curiosity’s arrival. I encourage you to look low in the west-southwest soon after 9 p.m. to view that remarkable planet in anticipation of events at its surface several hours later.
During two weeks from August 6 through August 20, Mars’ rapid position changes may be traced as it moves eastward in Virgo relative to Saturn. The planets appear closest to each other on the night of the 14th when they have less than three angular degrees of separation. Currently Mars has visual magnitude 1.14, while Saturn shines slightly brighter, at magnitude 0.79. The Red Planet is now 156 million miles from Earth, while Saturn with a range of 930 million miles, is six times further from us.
On August 9, the Last Quarter Moon rises at shortly before midnight.
As the Moon progresses along its orbit it passes the apparent vicinity of several bright planets, thereby serving as a marker for their identification.
During early mornings of Saturday August 11 and Sunday the 12th, the waning crescent Moon is in the early morning eastern sky near Jupiter.
The notable Perseid meteor shower may be seen at its annual peak from late on the evening of August 12 until morning twilight intervenes. During these times about one hundred “shooting stars” per hour are expected. Of course meteors are not actual stars, but bits of rock heated to incandescence by friction with air as they fall at speeds of dozens of miles per second through upper parts of our atmosphere. The Perseid meteor shower is well known due to its relatively high and consistent meteor count as well as occurrence at a time of year when vacationers in northern latitudes are often at sites with darker skies than those typical of suburban and urban locations. Only the brightest meteors can usually be seen from high population areas.
Perseid meteors derive their name from the constellation Perseus the direction from which these meteors appear to radiate. Fragments of rock that constitute Perseid meteors originated in the comet known as 109P/Swift-Tuttle.
Meteor watching is more comfortable and enjoyable if viewers recline in a chair while facing the direction of the radiant constellation. And, if you are planning a Perseid Watching Party, the radiant rises in the northeast around 10 p.m. then reaches the zenith about 4 a.m. Also, don’t forget mosquito repellent!
From about 4 a.m. until dawn on the mornings of the 13th and 14th of August the waning crescent Moon appears near the direction of Venus.
Before dawn on the 15th, a narrow lunar crescent might be seen adjacent to Mercury. By the middle of August Venus rapidly moves into the Gemini and, as always, is a vivid sight.
The evening of Tuesday the 21st the waxing crescent Moon forms an attractive triangular pattern in Virgo with rusty Mars and yellowish, slightly brighter Saturn.
When the Moon has helped provide conclusive identification of various planets during the month keep watching and reviewing planet locations. You can then use these objects as references for identifying stars in their vicinity.
First Quarter Moon is Friday August 24, when it rises in the narrow span of Scorpius containing part of the ecliptic. By the time the Moon sets just before midnight, it will have moved on into Ophiuchus, sometimes called the “thirteenth constellation of the zodiac”.
During August evenings we continue to savor rich stellar fields in and around the summer Milky Way. With a good guide to stars and constellations in hand, a red filtered flashlight to read by, under dark skies distant from city lights, clear warm nights provide extensive celestial sights and memories that may last a lifetime.
After tracing more obvious star patterns of the Summer Triangle and regions of Scorpius and Sagittarius near the center of the Milky Way Band, subtle groupings of fainter stars such as those in Delphinus, Sagitta, and Capricornus are lovely when seen under dark skies. If you have use of a telescope, summer evenings certainly provide many fine opportunities for enjoyment. Perhaps you have such an instrument packed away and seldom used. August is a fine time to take it out and start exploring the heavens. If it has been a while since your telescope has been out at night, try practicing with it during daylight lining up and looking at objects in your immediate neighborhood. In that way complications of setting up and aiming the telescope may be practiced with considerably more ease and success than trying to do so under dark skies. Even if you don’t have access to a telescope, binoculars and unaided eyes provide glorious visions of stars in dark skies.
If summer activities keep you up very late or you rise very early, by the middle of August the constellations Taurus, Orion, Auriga and Gemini, familiar sights during winter evenings, become increasingly apparent in the eastern pre-dawn sky. Their arrival provides celestial reminders that the next change of seasons is not too far off.