the solar system in june 2015

Dates and times are NZST (UT + 12 hours) unless otherwise specified. Rise and set times are for Wellington. They will vary by a few minutes elsewhere in NZ.

The southern winter solstice is on the morning of June 22. The Sun will be furthest north at 4.38 am (June 21, 16:38 UT).

Sunrise, sunset and twilight times in june

                       June  1  NZST                June 30  NZST
                    morning  evening                 morning  evening
            rise:   7.33am,  set:  5.03pm    rise:   7.45am,  set:  5.03pm
Twilights
  Civil:    starts: 7.06am,  ends: 5.31pm    starts: 7.16am,  ends: 5.32pm
  Nautical: starts: 6.31am,  ends: 6.06pm    starts: 6.42am,  ends: 6.07pm 
  Astro:    starts: 5.58am,  ends: 6.39pm    starts: 6.08am,  ends: 6.41pm

June PHASES OF THE MOON (times as shown by GUIDE)

  Full moon:     June  3 at  4.19 am (Jun  2, 16:19 UT)
  Last quarter:  June 10 at  3.42 am (Jun  9, 15:42 UT)
  New moon:      June 17 at  2.05 am (Jun 16, 14:05 UT)
  First quarter: June 24 at 11.03 pm (11:03 UT)

The planets in june

Mercury becomes visible in the dawn sky by the end of June. Venus gets a little higher in the evening sky and almost catches up with Jupiter at the end of the month. Saturn is easily visible all evening, setting well after midnight. Mars is at conjunction mid June so not visible this month.

Pluto will occult a magnitude 12.2 on the morning of June 30. The event is predicted to be visible from New Zealand.

Mercury was at inferior conjunction at the end of May, following which it moves into the morning sky. It will remain too close to the Sun to see for much of the month, but will be briefly visible in the brightening dawn sky towards the end of June.

The planet is in Taurus all month, starting June some 3.5° from the brightest star, Aldebaran. The two will then be too close to the Sun to see. Mercury moves away and up from Aldebaran until becoming stationary on June 12. Following that Mercury reverses direction and moves towards the star, with the two closest on the morning of June 24, 2° apart. With a magnitude 0.6 the planet will be a shade brighter than the star. At beginning of nautical twilight at 6.40 am when the Sun will be 12° below the horizon, the two will be a low 8° up, 30° round from east. Aldebaran will be to the right of Mercury and slightly higher.

By June 30, Mercury will have moved further to be below Aldebaran, but will have brightened to magnitude 0.0. At 7am it will again be some 8° above the horizon, only a few degrees east of northeast. Aldebaran will be 6.5° above it. The end of June will give the best chance to catch a glimpse of Mercury at its apparition in the morning sky.

Venus sets more than 3 hours after the Sun during the June, making it readily visible to the west after sunset. Half an hour after sunset will find Venus more than 20° up in a direction well north of west. It starts the month in Gemini, but from 3rd to the 24th will be crossing Cancer. During the last few days of the month it is in Leo, closing in on Jupiter. On the 30th the two will be just over half a degree apart. They are closer still on July 1.

The crescent moon joins the party on June 20 when it will be just over 5° from Venus and a little further from Jupiter.

Mars is at conjunction with the Sun mid June. At conjunction Mars will be 232 million km beyond the Sun and 384 million km from the Earth. Mars will be within 4° of the Sun throughout June, as seen from Earth, so much too close to the Sun to see.

Jupiter is an early evening object, setting about 10 pm on June 1 and a couple of minutes after Venus on the 30th. It moves from Cancer to Leo on June 1 ahead of Venus which almost catches up with Jupiter by the end of June.

The crescent moon is closest to Jupiter on the 21st when the two will be 5.5° apart. This is one evening after the moon's approach to Venus. By June 30 Venus and Jupiter will be a brilliant pair less than 1°.

Mutual events of jovian satellites

There are about 5 mutual events of Jupiter's Galilean satellites observable from NZ during June. One occurs when Jupiter is very low. Better placed ones are:

June  1,  Europa occults Io, mid event ca 8.46pm, duration 3.7 min,
          altitude ca 12°, az 307° 
June  4,  Ganymede occults Io, mid event ca 7.17pm, duration 29.1 min
          altitude ca 22°, az 324°  
June  6,  Io occults Europa, mid event ca 6.33pm, duration 5.6 min
          altitude ca 26°, az 333° 
June 22,  Europa occults Ganymede, mid event ca 7.25pm, duration 4.9 min
          altitude ca 15°, az 309°

This is almost the end of the current series of mutual events

Useful observations and timings of these events can be made by those set up for the video observation of minor planet occultations.

Users of Dave Herald's Occult program can generate their own predictions of these and other events. Hristo Pavlov's Occult Watcher programme will also list them and has diagrams showing the satellites relative to Jupiter. Details can also be found on the IMCCE web site, http://www.imcce.fr/phemu/ where predictions and requirements for observing and reporting information are available.

Saturn is visible all evening following its May 23 opposition. It doesn't set until several hours after midnight. The planet is in Libra moving slowly in a retrograde, westerly, sense as the Earth overtakes the planet.

The moon passes Saturn twice during the month. The first occasion is on June 1 when the 98% lit moon will be 5° from Saturn at midnight. The two will be only slightly further apart at 6 pm on the 2nd. The moon will pass Saturn again on June 29. Early evening the 91% lit moon will be a little under 4° below Saturn. They will be nearly 6° apart by midnight with the moon now to the upper right of Saturn due to the rotation of the sky.

Outer planets

Uranus is a morning object in Pisces rising more than 4 hours before the Sun on the 1st and rather over 6 hours before it on the 31st. The planet's magnitude is 5.9 to 5.8, so readily visible in binoculars

Neptune rises just before midnight on June 1 and 2 hours before on June 30.. The planet remains in Aquarius at magnitude 7.9. It is stationary on June 12 after which is recommences its easterly motion.

Pluto is in Sagittarius rising near 7.24 pm on the 1st and 2 hours earlier on the 30th about 24 minutes after sunset. Its magnitude will be 14.3. On the 30th Pluto will occult a 12.2 magnitude star at about 4.52am (June 29, 16:52 UT). The predicted path of the occultation is very promising for New Zealand. Video observations and light curves are wanted!

Brighter asteroids:

(1) Ceres is in Capricornus most of June, it moves into Microscopium on the last day of the month. It rises just before 9pm on the 1st and at 6.41 on the 30th. On June 22 Ceres will be 12', less than half the full moon's diameter from the 4.1 magnitude star omega Cap. The asteroid will be to the left of the star

(4) Vesta is a morning object in Pisces until June 21 when it crosses into Cetus. It brightens slightly during June from magnitude 7.9 to 7.6. Vesta rises at 1.18 am on June 1 and just after midnight on the 30th.

Brian Loader  
New Zealand

Dates and times are NZST (UT + 12 hours) from May 5 unless otherwise specified. Rise and set times are for Wellington. They will vary by a few minutes elsewhere in NZ.

Sunrise, sunset and twilight times in may

                       May  1  NZST                May 30  NZST
                    morning  evening                 morning  evening
            rise:   7.04am,  set:  5.30pm    rise:   7.33am,  set:  5.03pm
Twilights
  Civil:    starts: 6.38am,  ends: 5.57pm    starts: 7.05am,  ends: 5.33pm
  Nautical: starts: 6.06am,  ends: 6.30pm    starts: 6.31am,  ends: 6.06pm 
  Astro:    starts: 5.34am,  ends: 7.02pm    starts: 5.57am,  ends: 6.39pm

May phases of the moon (times as shown by guide)

  Full moon:     May  4 at  3.42 pm (03:42 UT)
  Last quarter:  May 11 at 10.36 pm (10:36 UT)
  New moon:      May 18 at  4.13 pm (04:13 UT)
  First quarter: May 26 at  5.19 am (May 25, 17:19 UT)

The planets in may

Mercury and Mars are both too close to the Sun to observe for a second month. Venus continues to get higher in the evening sky while Jupiter gets lower setting around 10 pm by the end of May, so is best observed early evening. Saturn is at opposition on May 23, so is best viewed late evening and early morning.

Mercury sets 45 minutes after the Sun on May 1. It is at its greatest elongation 21° east of the Sun on the 7th. Although it will then set 53 minutes after the Sun it will be too low for observation. It is at inferior conjunction between the Earth and Sun at the end of May. Mercury will then be about 2° south of the Sun with its unlit side towards the Earth. At conjunction Mercury will be 70 million km from the Sun and 82 million km from the Earth.

Venus sets 2 hours after the Sun on the 1st and 3 hours after it on the 31st. On May 1 Venus will be 13° up half an hours after sunset. The planet will be in Taurus some 3° above El Nath, beta Tau, at magnitude 1.7 the second brightest star in Taurus. Venus moves to the east into Gemini on the 8th. By the 31st, half an hour after sunset Venus will be 20° above the horizon to the north of northwest. It will then be 4° above Pollux, at magnitude 1.2 the brightest star in Gemini.

On the evening of May 21 the crescent moon, 11% lit will be 9° to the left of Venus. The following night the moon will be a similar distance above Venus.

Mars sets only half an hour after the Sun on the 1st. By the 31st this has reduced to only 10 minutes later. Conjunction occurs in mid June.

Jupiter will be best placed for viewing as the sky darkens following sunset. On the 1st it is highest, 31° and due north at transit, 6.49 pm. By the end of May, Jupiter transits at sunset and will be 30° up at 6pm an hour after sunset. Altitudes are for the latitude of Wellington. The planet will be a little higher further north and lower further south in NZ

The time Jupiter sets gets steady earlier during the month from a few minutes before midnight on the 1st to a few minutes after 10 pm on the 31st. It will be in Cancer rather distant from any bright stars. It will be moving slowly to the east in the direction of Regulus, but remain 15° from the star by the end of May.

Mutual events of jovian satellites

There are about 10 mutual events of Jupiter's Galilean satellites observable from NZ during May. Some occur very soon after sunset or when Jupiter is very low. Better placed one include:

May 3, Callisto occults Ganymede, mid event ca 10.40pm, duration 6.8 min, altitude ca 10° May 5, Io eclipses Europa, mid event ca 8.16pm, duration 5.3 min, magnitude change of Europa 1.5, so easy to detect May 13, Ganymede occults Io, mid event ca 6.07pm, duration 5.5 min May 17, Io occults Ganymede, mid event ca 8.12pm, duration 4.9 min May 20, Ganymede occults Io, mid event ca 9.05pm, duration 6.4 min May 25, Europa occults Io, mid event ca 6.28pm, duration 3.5 min May 27, Ganymede occults Europa, mid event ca 8.03pm, duration 7.3 min,

this occultation is total for about 90 seconds.

Useful observations and timings of these events can be made by those set up for the video observation of minor planet occultations.

Users of Dave Herald's Occult program can generate their own predictions of these and other events. Hristo Pavlov's Occult Watcher programme will also list them and has diagrams showing the satellites relative to Jupiter. Details can also be found on the IMCCE web site, <a href="http://www.imcce.fr/phemu/">http://www.imcce.fr/phemu/</a> where predictions and requirements for observing and reporting information are available.

Saturn is at opposition on May 23. It rises just over an hour after sunset on May 1 and about half an hour before sunset on May 31. The planet starts the month in Scorpius near beta1 Sco (mag 2.6). It moves slowly to the west through the stars during May, crossing into Libra on May 11.

At opposition on May 24, Saturn will be slightly less than 9 AU, 1341 million km from the Earth and 10 AU, 1493 million km from the Sun.

The almost full moon will be just under 4° to the left of Saturn on the evening of May 5. The two are closest about 4am on the morning of May 6.

At present Saturn's north pole is tilted 25° towards the Earth. This brings the northern surface of the rings well into view. They should be visible in binoculars, although a small telescope is likely to give a better view.

Outer planets

Uranus is a morning object in Pisces rising 2 hours before the Sun on the 1st and rather over 4 hours before the Sun on the 31st. The planet's magnitude is 5.9, so readily visible in binoculars

Neptune rise a little over 5 hours before the Sun on May 1. By the 31st it rises just before midnight. The planet remains in Aquarius at magnitude 7.9

Pluto is in Sagittarius rising near 9.30 pm on the 1st and 2 hours earlier on the 31st. Its magnitude is 14.3.

Brighter asteroids:

(1) Ceres is in Capricornus during May, its magnitude ranging from 8.9 to 8.5 through the month. It rises a little before 11 pm on the 1st and at 9 pm on the 31st.

(4) Vesta is a morning object in Aquarius for most of May, but moves into Pisces on the 29th. Its magnitude is close to 8.0 all month. Vesta rises at 2.20 am on May 1 and 1.20 am on the 31st.

Brian Loader  
New Zealand