August Moon & Planet data for 2013


The Solar System In August 2013

Phases Of The Moon (times as shown by guide)

New moon:      August  7 at  9.51 pm NZST (Aug 6, 21:51 UT)
First quarter: August 14 at 10.56 pm NZST        (10:56 UT)
Full moon:     August 21 at  1.45 pm NZST        (01:45 UT)
Last quarter   August 28 at  9.35 pm NZST        (09:35 UT)

The Planets In August

Saturn remains visible in the evening sky throughout August, it gets lower during the month especially later evening. Venus is visible in the early part of the evening and gets higher during the month.

Mercury, Mars and Jupiter all start August as morning objects. On the 1st, forty minutes before sunrise, they will be very low to the northeast. Jupiter will be highest 8° up and so quite easily visible at magnitude -1.9. By the end of August Mercury will have disappeared, the altitude of Mars, 40 minutes before sunrise, will be almost unchanged, Jupiter will be nearly twice as high.

Planets In The Evening Sky: Saturn and Venus.

VENUS will be the first object to appear in the evening sky, visible at sunset or earlier. On August 1, 30 minutes after sunset it will be about 22° above the horizon.

By that time, as the sky darkens, SATURN will also be visible almost due north well up in the sky with Spica 12° to its left. Later in the evening, as the two swing around to the west the rotation of the sky brings Spica down to the lower left of Saturn. Saturn will set a little before 1am.

At the end of August Venus will be about 30° above the horizon half-an-hour after sunset and set more than 3 hours after the Sun. By the 31st the planet will only be 7° below Spica.

Saturn, on the other hand, will be getting lower, but still higher than Venus, now to the northwest, 14° from Spica, to the star’s upper right. The planet will set about 11 pm, so will be best observed early evening.

The moon moves through this part of the sky fairly early in the month. On the 10th, as a thin crescent 10% lit, it will be 5° above Venus. On the 12th the 27.5% lit moon will be just over 1° below Spica, the two being closest about 9 pm. The following night, the moon now 38% lit is 2.4° to the upper left of Saturn.

Mercury will be a very low evening object by the end of August, but it sets only half an hour after the Sun on the 31st, so is not visible.

JUPITER, MARS and MERCURY in the morning sky.

At the beginning of August the three planets will all be low in the dawn sky. Jupiter will be the highest, about 8° up 45 minutes before sunrise. At the same time Mars, at magnitude 1.6, will be just over 5° up, while Mercury is 3.5° up and a little brighter at magnitude 0. Only Jupiter, magnitude -1.9 is likely to be reasonably easy to see by eye.

On the morning of the 4th the waning moon, a thin crescent 8.5% lit, will be just over 3° above Jupiter.

During the month, Jupiter will gradually get higher, Mars hardly change in height while Mercury will close in on the Sun, so there is little chance of seeing the latter.

On the 24th Mercury is at superior conjunction with the Sun, 1.36 AU or 203 million km from the Earth and 52 million km beyond the Sun. After conjunction Mercury will become an evening object, but remains too close to the Sun to be visible during the remainder of August.

By the 31st Jupiter will be an easy object in the early dawn sky, 40 minutes before sunrise it will be 15° above the horizon shining brightly to the northeast.

Outer Planets

NEPTUNE is at opposition on August 27, when it will be 29.0 AU, 4334 million km from the Earth and a further 150 million km from the Sun. At opposition its magnitude is 7.8. Neptune is in Aquarius.

URANUS is more than 3 hours behind Neptune, so it will not rise until late evening early in the month and mid evening by the end. Its magnitude is 5.7, the planet being in Pisces.

Brighter Asteroids:

Both (1) Ceres and (4) Vesta are at conjunction with the Sun during August, Vesta on August 5 and Ceres August 16. At opposition Vesta will be 3.47 AU, 519 million km from the Earth and 367 million km from the Sun. From the point of view of the Earth, Vesta will pass 2.5° north of the Sun. Ceres at opposition is slightly further away, 533 million km from Earth and 3883 from the Sun. It passes 7° north of the Sun.

While Ceres and Vesta are too close to the Sun to observe, a number of other asteroids are in binocular reach during August, with two being at opposition.

(2) Pallas is in Monoceros, magnitude 9.1, changing little during the month

(3) Juno Starts the month in Aquarius magnitude 9.0. It soon moves into Aquila where it is at opposition on August 14, still magnitude 9.0. By the end of August it will have dimmed a little to 9.3.

(7) Iris is also in Aquarius, it is at opposition on August 16 at magnitude 7.9, so at that date is the brightest asteroid.

(8) Flora is past opposition, its magnitude dims from 9.0 to 9.6 during the month. It is in Sagittarius where it will occult a number of faint stars.

(324) Bamberga brightens rapidly during the month, starting at magnitude 9.4, it reaches 8.5 by the 31st. The asteroid is in Pisces. Opposition is in September.

Brian Loader


The follwing table lists various solar system object events during August. A list of astronomical terms used in may be found after the table.

August 1 Aldebaran 3.1 degrees south of the Moon
August 2 Moon northern most declination (20.0 degrees)
August 3 Moon at apogee
Jupiter 4.0 degrees north of the Moon
August 4 Mars 5.1 degrees north of the Moon
August 5 Mercury 4.3 degrees north of the Moon
August 6 Moon new
August 8 Regulus 5.2 degrees north of the Moon
August 9 Venus 4.9 degrees north of the Moon
August 12 Spica 0.5 degrees south of the Moon Occn
August 13 Saturn 2.8 degrees north of the Moon
August 14 Moon first quarter
August 16 Moon southern most declination (-19.9 degrees)
August 17 Pluto 1.2 degrees south of the Moon Occn
Mars 5.8 degrees south of Pollux
August 19 Moon at perigee
August 21 Moon full
Neptune 5.3 degrees south of the Moon
August 23 Mercury 1.3 degrees north of Regulus
August 24 Uranus 3.2 degrees south of the Moon
Mercury superior conjunction
August 27 Neptune at opposition
August 28 Moon last quarter
Aldebaran 2.9 degrees south of the Moon
August 29 Moon northern most declination (19.8 degrees)
August 30 Moon at apogee
August 31 Jupiter 4.4 degrees north of the Moon
  • apogee: Furtherest point in the orbit of a body orbiting the Earth
  • declination: 'Latitude' for celestial objects. The distance in degress above (north) or below (south) the celestial equator.
  • perigee: Nearest point in the orbit of a body orbiting the Earth
  • superior conjunction: Conjunction where the Sun is between the Earth another solar system object