August 2012 Sky Events

Moon Phases

Wed., August 1, 11:27 p.m. EDT

Full Moon

The full moon of August is usually called the grain moon. In Algonquian it is called the sturgeon moon. Other names are red moon, green corn moon, lightning moon and dog moon. In Hindi it is known as narali poornima or raksha bandhan. Its Sinhala (Buddhist) name is nikini. The full moon rises around sunset and sets around sunrise, the only night in the month when the moon is in the sky all night long. The rest of the month, the moon spends at least some time in the daytime sky.

Thu., August 9, 2:55 p.m. EDT

Last Quarter Moon

The last or third quarter moon rises around 11:20 p.m. and sets around 2:20 p.m. It is most easily seen just after sunrise in the southern sky.

Fri., August 17, 11:54 a.m. EDT

New Moon

The moon is not visible on the date of new moon because it is too close to the sun, but can be seen low in the east as a narrow crescent a morning or two before, just before sunrise. It is visible low in the west an evening or two after new moon.

Fri., August 24, 10:54 a.m. EDT

First Quarter Moon

The first quarter moon rises around 2:30 p.m. and sets around 12:20 a.m.

Fri., August 31, 9:58 a.m. EDT

Full Moon

There is a second full moon this month, what is sometimes called a ”blue moon.” There is nothing unusual about the appearance of this full moon; it gets its name from the fact that having two full moons in a month is a rare event, “as rare as a blue moon.”

This is usually called the fruit moon. In Algonquian it is called the harvest moon, a month earlier than the usual harvest moon. Other names are corn moon and barley moon. In Hindi it is known as bhadrapad poornima. Its Sinhala (Buddhist) name is binara. The full moon rises around sunset and sets around sunrise, the only night in the month when the moon is in the sky all night long. The rest of the month, the moon spends at least some time in the daytime sky.

Observing Highlights

Mon., August 6, morning

Double shadow transit on Jupiter

Multiple events involving Jupiter’s moons and their shadows:

EDT          PDT                                 

2:47 a.m.                    Shadow of Ganymede starts across Jupiter’s disk

3:27 a.m.                    Europa disappears into Jupiter’s shadow

4:07 a.m.                    Shadow of Io starts across Jupiter’s disk

4:38 a.m.                    Shadow of Ganymede leaves disk

5:18 a.m.                    Io starts across Jupiter’s disk

5:50 a.m.  2:50 a.m.  Europa emerges from Jupiter’s shadow

5:53 a.m.  2:53 a.m.  Europa disappears behind Jupiter

6:15 a.m.  3:15 a.m.  Shadow of Io leaves disk

                  4:27 a.m.  Io leaves disk

                  4:42 a.m.  Ganymede starts across Jupiter’s disk

                  5:15 a.m.  Europa reappears from behind Jupiter

A 90mm telescope is needed to see the shadows; at least 125mm to see the satellites in transit.

Sat., August 11, morning

Jupiter occulted by the moon

Jupiter and its moons will be occulted by the Moon as seen from Indonesia, Marshall Islands, and Hawaii. Elsewhere will see a close conjunction between Jupiter and the moon.

Sun., August 12, after midnight

Perseid meteor shower peaks

The Perseid meteor shower, usually the most reliable meteor shower of the year, peaks just around dawn. There will be a thin crescent moon rising around 1:30, which will interfere a bit with the fainter meteors. This shower has a broad peak, so there should be plenty of Perseids visible in the nights before and after the peak.

Mon., August 13, dawn

Jupiter, Venus and the moon

A triple conjunction frames the crescent moon with the two brightest planets, Venus and Jupiter. They will be surrounded by half a dozen first magnitude stars.

Tue., August 14, early evening

Saturn, Mars, and Spica

A close encounter between planets Saturn and Mars, along with first magnitude star Spica, Alpha Virginis.

Thu., August 16, dawn

Mercury and Venus at maximum elongation

Mercury and Venus never stary far from the Sun, but this morning they’re both about as far as they can get from it. Mercury is at maximum western elongation this morning, and Venus was at maximum western elongation yesterday morning. A thin crescent moon will help you to locate Mercury.

Tue., August 21, early evening

Saturn, Mars, Spica, and the moon

The moon joins a close grouping of planets Saturn and Mars, and the bright star Spica.

Wed., August 22, morning

Satellite action on Jupiter

Multiple events involving Jupiter’s moons and their shadows:

EDT          PDT                                 

2:22 a.m.                    Shadow of Io starts across Jupiter’s disk

3:20 a.m.                    Shadow of Europa starts across Jupiter’s disk

3:40 a.m.                    Io starts across Jupiter’s disk

4:30 a.m.                    Shadow of Io leaves disk

5:42 a.m.  2:42 a.m.   Shadow of Europa leaves disk

5:48 a.m.  2:48 a.m.    Io leaves disk

6:03 a.m.  3:03 a.m.    Europa starts across Jupiter’s disk

                  5:24 a.m.    Europa leaves disk

A 90mm telescope is needed to see the shadows; at least 125mm to see the satellites in transit.

Fri., August 24, midnight

Neptune at opposition

You can find Neptune with binoculars using the two easternmost stars in Capricornus, Deneb Algiedi and Nashira, as shown in this chart.

Planets

Mercury is in the morning sky for most of the month, best observed from the southern hemisphere. Greatest western elongation from the Sun is on August 16.

Venus is now a morning “star,” shining brightly before sunrise. Greatest western elongation from the Sun is on August 15.

Mars is shrinking rapidly in size and brightness, located in Virgo. Mars is low in the southwest at sunset and sets around 10:30 p.m..

Jupiter is in the morning sky in Taurus. It is close to Venus all month.

Saturn is low in the southwest in Virgo, setting around 10:30 p.m.

Uranus continues its sojourn into the strange “waters” of the constellation Cetus this month, an orbital anomaly.

Neptune is in opposition in Aquarius on August 24, and is visible all night long.

Geoff Gaherty

Starry Night Software Support