The Solar System in July 2016

Dates and times shown are NZST (UT + 12 hours) unless otherwise stated.

Rise and set times are for Wellington. They will vary by a few minutes elsewhere in NZ.

Sunrise, sunset and twilight times in July

                            July  1  NZST                    July 31  NZST
                    morning  evening                 morning  evening
       SUN: rise:   7.44am,  set:  5.04pm    rise:   7.27am,  set:  5.27pm
Twilights
  Civil:    starts: 7.16am,  ends: 5.33pm    starts: 7.00am,  ends: 5.55pm
  Nautical: starts: 6.42am,  ends: 6.08pm    starts: 6.27am,  ends: 6.28pm
  Astro:    starts: 6.08am,  ends: 6.41pm    starts: 5.54am,  ends: 7.01pm

July phases of the Moon (times as shown by GUIDE)

          New moon:      July  4 at 11.01 pm (11:01 UT)
  First quarter: July 12 at 12.52 pm (00:52 UT)
  Full moon:     July 20 at 10.57 am (July 19, 22:57 UT)
  Last quarter   July 27 at 11.00 am (July 26, 23:00 UT)

The planets in July

All five naked eye planets are visible during some part of the evening by late July. Mercury becomes easily visible in the early evening sky towards the end of the month. Venus will be lower Mercury from the second part of July. Mars remains prominent although fading a little while Jupiter gets lower to the east. Saturn will not be far from Mars.

Mercury is at superior conjunction on July 7, when it will be 47 million km (0.314 AU) beyond the Sun and 199 million km (1.33 AU) from the Earth. Before conjunction Mercury will be too close to the Sun to observe, after conjunction it becomes an evening object setting after the Sun. By the end of July the planet will set nearly 2 hours later than the Sun. On the evenings of the 30th and 31st Mercury will be less than a degree from Regulus with Mercury at magnitude -0.1, 1.5 magnitudes brighter than Regulus. About an hour after sunset the two will be 7° up in a direction half way between west and northwest.

Earlier in July on the 16th, Mercury and Venus will be less than a degree apart. But the two planets will set only 45 minutes after the Sun, making observation difficult. At 5.30 with the Sun only 4° below the horizon, the planets will be a low 4° above it. Venus at magnitude -3.9 May be detectable, Mercury's magnitude being-1.1.

Venus, in the very early evening sky will set less than half an hour after the Sun on the 1st and about 50 minutes after the Sun on the 31st. So it will be a very low object at best.

Venus starts the month in Gemini, moves across Cancer between July 10 and 26 and ends the month in Leo heading towards Regulus.

Mars remains a prominent evening object although loses a little of its brightness during July as the Earth recedes from it. By the end of the month it will still be bright at magnitude -0.8.

The planet will be in Libra moving rather slowly to the east after being stationary at the end of June. By the end of July, Mars will be poised to cross into Scorpius, heading towards its rival Antares.

The moon passes Mars mid month, but the two do not get very close. They are about 10° apart on the nights of July 14 and 15.

Jupiter becomes an early evening object during July, setting just after 9pm on the 31st. It remains in Leo.

The 25% lit crescent moon will be just over 1° from Jupiter on July 9. An occultation of the planet is only visible from the Southern Ocean to the south of Australia and parts of Antarctica beyond.

Saturn is well paced for evening viewing during July, a bright object about 6° from Antares which it will outshine by nearly a magnitude. The colour of the two makes a contrast. The planet is in Ophiuchus moving slowly in a retrograde sense to the west.

The 87% lit moon will be just under 4° from Saturn on the evening of July 16.

Outer planets

Uranus, at magnitude 5.9, is a morning object in Pisces although it will rise just before midnight by the end of July. It is stationary on the 30th , with its position changing only slightly during the month.

Neptune rises near 10 pm at the beginning of the month advancing to 8am by the month's end. The planet, at magnitude 7.9, is in Aquarius and will be about half a degree from the 3.7 magnitude star lambda Aqr. In the mid to late evening Neptune will be to the right of the star early in the month gradually moving up to be at the star's upper right by the end of the month. There are no stars as bright as Neptune between them to cause confusion.

Pluto at magnitude 14.3 is also in evening sky during July. The planet remains in Sagittarius. It moves away from the 2.9 magnitude star pi Sgr during July, starting only 8 arc-minutes from the star on the 1st, the distance increasing to almost a degree by the 31st.

Minor planets

(1) Ceres, is in Cetus during July moving to the east. It brightens slightly through the month, from 9.2 to 8.9.. It rises at 1.30 am on the 1st and close to midnight on the 31st.

(4) Vesta rises 100 minutes before the Sun on July 1 and just after 5 am on the 31st. Starting the month in Taurus, Vesta will be less than half a degree from the magnitude 3 star zeta Tau on the morning of the 14th. On the 21st the asteroid will cross into Orion.

Brian Loader  
New Zealand