July Moon & Planet data for 2013

Phases of the moon (times as shown by guide)

New moon:      July  8 at  7.14 pm NZST (07:14 UT)
First quarter: July 16 at  3.18 pm NZST (03:18 UT)
Full moon:     July 23 at  6.16 am NZST (Jul 22, 18:16 UT)
Last quarter   July 30 at  5.43 am NZST (Jul 29, 17:43 UT)

The Earth is at aphelion, its greatest distance from the Sun for the year, on July 6 at 2 am, when the distance will be 1.0167 AU, 152.1 million km.

The planets in July

Saturn is visible all evening throughout July. Venus will gradually get to be more visible to the northwest for a little longer following sunset.

Mercury starts the month as an evening object but difficult to see. Later in the month it will become a morning object, low in the dawn sky and quite close to Jupiter and Mars.

Planets in the evening sky: Saturn, Venus and at first Mercury.

SATURN will remain an easy evening object during July, best viewed early evening, especially later in the month when it will set round about 1 am. The planet will remain in Virgo some 12 degrees to the right of Spica. The two make an obvious pair high to the north in the early part of the evening.

With the north pole of Saturn now tilted towards the Earth at an angle 17°, the rings are readily visible through a small telescope.

The first quarter moon will be about 1 degree from Spica early in the evening of July 16, the following evening the moon will be 4.5 degrees to the upper right of Saturn.

Saturn is stationary on July 4 when its westerly, retrograde motion will come to an end as the faster moving Earth swings away from the outer planet. Saturn will then resume its normal easterly track through the stars, slowly taking it away from Spica.

VENUS will only be visible early evening. It sets two hours after the Sun on the 1st advancing to two and three-quarter hours later on the 31st. Look for the planet soon after sunset to the northwest. On July 1, half an hour after the Sun goes down, the planet will be twelve degrees above the horizon. This will increase to a good twenty degrees by the 31st.

On the 10th of July the 3.4% lit crescent moon will be 9° to the left of Venus and virtually at the same level.

MERCURY will be 13 degrees to the lower left of Venus on July 1 when it will set just over an hour after the Sun. At magnitude 3.1, Mercury will be very difficult to locate in the evening twilight. Over the next few evenings the elongation of Mercury from the Sun will decrease quite rapidly until it is at inferior conjunction with the Sun on the 10th. After conjunction Mercury will move into the morning sky.

Jupiter, Mars and Mercury in the morning sky.

Jupiter passes Mars towards the end of July when low in the dawn sky. The two are closest on the mornings of July 22 and 23 when the planets will be 49 arc-minutes apart. Mars will then be to the lower left of Jupiter and, at magnitude 1.6, a lot fainter. The previous two mornings the planets will be a degree or more apart with Mars to the left of Jupiter. Their separation will increase again on the 24th and 25th with Mars now almost directly below Jupiter.

Early in July Jupiter will rise a little over 30 minutes before the Sun, making it a difficult object. Mars will rise half an hour or so earlier. By the end of July, Jupiter will rise nearly an hour and three-quarters before the Sun, so it will be easier to see, low to the northeast. Mars will have been left behind, rising about 90 minutes before the Sun.

Mercury is at inferior conjunction on the 9th when it will pass some 4.5 degrees south of the Sun. It then moves into the morning sky to be below Jupiter and Mars. By the end of July it will rise about an hour and a quarter before the Sun, so will remain low and a difficult object in the dawn sky. Mercury will by then have brightened noticeably, reaching magnitude 0.2 by July 31st when it will be at its greatest elongation, 20° west of the Sun.

In the second half of July all three planets will be in Gemini, so forming a fairly tight group. Mars is in Taurus for the first half of the month, moving into Gemini on the 15th.

At the end of July, three-quarters of an hour before sunrise, Jupiter will be 8° up to the northeast. Mars, much fainter at mag 1.6 will be 4° to the lower right of Jupiter. Mercury will be 7° to the right of Mars, slightly lower and brighter at mag 0.2. The star Betelgeuse in Orion, will be nearly 20° above Jupiter and Procyon will be some 24° to Jupiter’s right. Both stars have a magnitude close to 0.5, so will be only slightly fainter than Mercury.

Outer planets

URANUS will rise at midnight mid July. It will be in Pisces at magnitude 5.8.

NEPTUNE rises more than 3 hours earlier than Uranus, so by 7.45 pm at the end of the month. During July, the planet is in Aquarius with a magnitude 7.8.

Brighter asteroids

Both (1) Ceres, magnitude 8.8, and (4) Vesta, magnitude 8.6, start July in Cancer.

They are below Venus in the evening sky, so setting shortly after the Sun, making them virtually unobservable. Both are in conjunction with the Sun during August.

Other asteroids brighten to become possible binocular objects during July.

(3) Juno brightens from 9.7 to 9.1 during the month, and (7) Iris from 9.3 to 8.4. Both are in Aquarius and about 15° apart. Early in July they rise mid evening, so are essentially late evening objects. They are at opposition mid August reaching magnitudes 9.0 and 7.9 respectively.

(8) Flora is at opposition on July 20 at magnitude 8.7. It starts the month in Capricornus at magnitude 9.3. Flora moves into Sagittarius on the 11th.

(2) Pallas is at magnitude 9.2 in Orion, so not near opposition.

-- Brian Loader

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

July 1 Pluto at opposition
July 5 Aldebaran 3.3 degrees south of the Moon
Earth at aphelion
July 6 Moon northern most declination (20.1 degrees)
Mars 3.7 degrees north of the Moon
July 7 Moon at apogee
Jupiter 3.5 degrees north of the Moon
July 8 Moon new
Mercury 0.1 degrees south of the Moon Occn
July 9 Saturn stationary
Mercury inferior conjunction
July 11 Regulus 5.4 degrees north of the Moon
July 16 Moon first quarter
Spica 0.3 degrees south of the Moon Occn
Saturn 3.2 degrees north of the Moon
July 17 Uranus stationary
July 20 Moon southern most declination (-20.0 degrees)
Mercury stationary
July 21 Pluto 1.0 degrees south of the Moon Occn
Moon at perigee
July 22 Mars 0.8 degrees north of Jupiter
Venus 1.1 degrees north of Regulus
Moon full
July 25 Neptune 5.4 degrees south of the Moon
July 27 Uranus 3.3 degrees south of the Moon
July 29 Moon last quarter
July 30 Mercury greatest elong W(20)
  • aphelion: Furtherest point in the orbit of a body orbiting the Sun
  • 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.
  • inferior conjunction: Conjunction where a solar system object is between the Earth and the Sun
  • perigee: Nearest point in the orbit of a body orbiting the Earth