On three occasions during August, Callisto will be the only one of the 4 Galilean satellites of Jupiter visible clear of the planet. See the diary of events for dates and times.
Orbital diagrams for the inner planets December 2008 to March 2009, April to July 2009, July to November 2009 and the outer planets for 2009.
| Date (NZDT) | Diary of Solar System Events in August 2009 for New Zealand |
| August 1 | 76% lit waxing Moon less than 1.5° from Antares, magnitude 1.1, the brightest star in Scorpius. Becoming closest in the early morning sky |
| August 2 | Moon furthest south, resulting in the highest southern hemisphere transit for the month. |
| August 3 | Mercury three-quarters degree from star Regulus, early evening sky. |
| August 4 | Moon at apogee, its greatest distance from the Earth for the Lunar month, 406024 km. |
| August 6 | Full Moon at 12:55pm NZST (00:55 UT).
A 20% partial penumbral eclipse not visible from New Zealand. |
| August 6/7 | Full Moon 4° from Jupiter and Neptune. Closest in morning sky. |
| August 9/10 | 89% lit waning Moon 5.5° from Uranus. Closest about midnight. |
| August 10 | Rings of Saturn edge on to Sun. |
| August 14 | Moon at last quarter 6:55am NZST (Aug 13, 18:55 UT). |
| August 15 | Jupiter at opposition. |
| August 16 | Moon furthest north, resulting in the lowest southern hemisphere transit for the month. |
| August 16 | Moon, 28% lit, 6° from Mars, morning sky. |
| August 16 & 17 | Mercury 3° from Saturn, early evening sky. |
| August 16/17 | Jupiter with only one satellite, Callisto, visible clear of planet from 11:23pm to 12:15am (NZST). |
| August 18 | Neptune at opposition. |
| August 18 | Crescent Moon, 10% lit, 3° from Venus, morning sky. |
| August 19 | Moon at perigee, its closest to the Earth for the Lunar month, 359639 km. |
| August 20 | New Moon at 10:01 pm, (10:01 UT). |
| August 22 | 5% lit crescent Moon 3° from Mercury and 6° from Saturn, early evening sky. |
| August 24 | Jupiter with only one satellite, Callisto, visible clear of planet from 1:06am to 3:28am (NZST). |
| August 24 | 19% waxing Moon 3.3° from Spica, magnitude 1.1, brightest star in Virgo. |
| August 24 | Mercury at greatest elongation 27° east of Sun. |
| August 27 | Moon at first quarter 11:42pm NZST (11:42 UT). |
| August 28 | 58% lit waxing Moon 4° from Antares, magnitude 1.1, the brightest star in Scorpius. |
| August 29 | Moon furthest south, resulting in the highest southern hemisphere transit for the month. |
| August 31 | Jupiter with only one satellite, Callisto, visible clear of planet from 3am to just after 5:30am (NZST). |
| August 31 | Moon at apogee, its greatest distance from the Earth for the Lunar month, 405270 km. |
Return to Top of page. Diary of events. RASNZ home page
MERCURY puts on its best evening display of the year during August
for southern hemisphere viewers. This will give a good opportunity to see this elusive planet.
On August 1 it will set about 90 minutes after the Sun at the latitude of New Zealand. 45
minutes after sunset the planet will be rather low, only 7° above the horizon and 3°
below the star Regulus. Mercury will be nearly two magnitudes brighter than the star and should
be visible in the twilit sky.
As the month progresses Mercury will set later, so that by the second half of August it will set about two and a half hours after the Sun. On August 16 and 17 the planet will be 3° to the left of Saturn and 16° above the horizon 45 minutes after sunset so making it easier to see. Mercury will be a magnitude brighter than Saturn. Mercury will maintain this altitude 45 minutes after sunset for the rest of August making it an easy early evening object.
VENUS, still brilliant in the morning sky, will rise about two and
a half hours before the Sun at the beginning of August and be some 17° up 15 minutes before
sunrise. The planet will gradually rise later during the month, getting lower in the morning
sky before sunrise. By the end of August it will be only 10° up shortly before sunrise.
On August 2, Venus will move into Gemini from the small, northern-most lobe of Orion. It will be crossing Gemini for most of August, until it moves into Cancer on August 26. On that morning, Venus will be half a degree from the asteroid Vesta. At magnitude 8.4 Vesta may be visible in binoculars while the sky is still almost dark, although low altitude could well make it a difficult object. Vesta will be at the 7 o'clock position compared to Venus, that is to its lower left. A 7.2 star will lie between the two planetary objects, and be considerably brighter than Vesta.
Earlier in the month, on the morning of August 18, a thin crescent Moon, 10% lit, will be less than 3° to the lower left of Venus, making a nice pair low to the northeast.
MARS rises soon after 4am at the beginning of August and a little
before 4am at the end of the month, as seen from most parts of New Zealand.
On August 1, the planet will be about 6° directly below the Aldebaran, the brightest star in Taurus. Aldebaran is a reddish star which at magnitude 1 will appear similar to Mars in brightness and colour.
During August Mars will move to the east through Taurus, with the 28% lit waning Moon being 6° to its left on the morning of the 16th. By August 27 Mars will have moved into Gemini, to end the month some 17° below another red star, Betelgeuse. By then Mars will be to the north of northeast at a modest altitude of 18° some 45 minutes before sunrise.
JUPITER is at opposition, that is on the opposite side of the Earth
to the Sun, on August 15. So by then Jupiter will be in the sky all night and at its highest
soon after midnight. By the end of the month the planet will be readily visible to the east in
the early evening by the time the sky is dark.
During August the Jupiter continues to move to the west through the stars taking it further away from Neptune, the two being nearly 5° apart by the end of the month. Neptune will be almost directly below Jupiter early in the evening.
The full Moon will pass Jupiter on the night of August 6. They will be just over 6° apart early evening, 5° at midnight and 4° near dawn on the morning of the 7th.
SATURN will set before 9pm on August 1, a time advancing to about
7.15pm by the end of the month. This latter is only some 70 minutes after sunset, so by then
opportunities for viewing the planet will be limited.
The rings, as seen from the Earth, are going to continue to close during August, so becoming very narrow. In addition, they will be edge on to the Sun on August 10, so it will be interesting to see how much they are then visible. After August 10 the Sun will be illuminating the north face of the rings, while from Earth the south face will still be in view, albeit very obliquely. As a result the rings themselves may be very difficult to see, although their shadow on the planet may be fairly distinct as a fine black line.
The rings are edge on only once in about 15 years (half of the time it takes Saturn to go round the Sun), so it will be a long time before this happens again. It is unfortunate that the planet will be fairly poorly placed for viewing and setting early evening.
Mercury passes Saturn on the evenings of August 16 and 17, with Mercury some 3° to the left of Saturn. Saturn will be the fainter object by 1 magnitude. Three-quarters of an hour after sunset, the two will be 16° up in a direction half way between west and northwest.
On August 22, with Mercury now 6° above Saturn, the two planets will be joined by a thin crescent Moon. The Moon will be closer to Mercury, some 3.5° to its lower left, as against over 6° to the upper left of Saturn.