the solar system in February 2016

Dates and times shown are NZDT (UT + 13 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 February

                            February  1  NZDT                February 29  NZDT
                    morning  evening                 morning  evening
       SUN: rise:   6.23am,  set:  8.44pm    rise:   6.58am,  set:  8.07pm
Twilights
  Civil:    starts: 5.55am,  ends: 9.13pm    starts: 6.32am,  ends: 8.34pm
  Nautical: starts: 5.17am,  ends: 9.51pm    starts: 5.58am,  ends: 9.07pm 
  Astro:    starts: 4.34am,  ends:10.33pm    starts: 5.23am,  ends: 9.43pm

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

          Last quarter:  February  1 at  4.28 pm (03:28 UT)
  New moon:      February  9 at  3.39 am (Feb  8, 14:39 UT)
  First quarter: February 15 at  8.47 pm (07:47 UT) 
  Full moon:     February 23 at  7.20 am (Feb 22, 18:20 UT)

The planets in February

Jupiter will be in the sky from soon after sunset by the end of February. The other planets remain objects of the morning sky. Venus and Mercury are a close pair in the dawn sky and will be an interesting to watch as their distance apart vary during the month. The asteroid (5) Astraea is at a particularly good opposition mid February.

Mercury and VENUS form a pair of planets rather low in the dawn sky throughout February. At the beginning of the month both planets will be in Sagittarius. During February they move into Capricornus, Mercury on the 14th and Venus 3 mornings later.

On the morning of the 1st, Mercury rises almost 2 hours before the Sun, with Venus rising some 35 minutes earlier. Mercury will be half a degree below the 2.9 magnitude star pi Sgr, with Venus some 7 degrees above Mercury.

During the first half of February Venus will close in on Mercury until the two are some 4 degrees apart mid month. After that as Mercury's rate of motion increases it will draw further ahead of Venus until the two are again 7 degrees apart by the end of the month. Mercury will remain a few degrees below Venus and a little to its right all month.

Mercury's magnitude brightens from 0.1 to -0.3 during February. It reaches its greatest elongation, 26 degrees west of the Sun on the 7th. By the end of February Mercury rises some 95 minutes before the Sun, with Venus rising half an hour earlier. An hour before sunrise, Mercury will be only 6 degrees above the horizon

Mars rises half an hour after midnight on the 1st advancing to 11:45 pm by the 29th. The planet is in Libra, near the wide binary star alpha Lib at the beginning of the month. The two are closest on the 2nd when Mars, magnitude 0.8, will be a degree below the pair, with the 45% lit moon 4.5 degrees lower than Mars. For the rest of the month Mars makes its way eastwards through Libra but doesn't pass close to any bright stars.

At midnight on the 29th February the moon will again be near Mars, some 5.5 degrees from the planet which will have brightened to magnitude 0.3. A few hours later, on the morning of March 1, the two will be 4 degrees apart

Jupiter is in Leo during February. On the 1st it rises about 10.20 pm, by the end of February it will rise almost 2 hours earlier, some 15 minutes after the Sun sets, so the planet should be readily visible by mid evening.

In the late evening of February 24, the almost full moon will be 4 degrees to the left of Jupiter; their separation increases to 6.5 degrees a little before sunrise the following morning when Jupiter will appear below the moon.

Saturn rises shortly after 2 am on the 1st and 20 minutes after midnight on the 29th. So it is still a morning object. The planet is in Ophiuchus about 8 degrees below Antares, as seen in the morning sky. At magnitude 0.5, Saturn is a little brighter than the star.

On the morning of February 4, the 26% lit moon will be 4 degrees to the lower left of Saturn

Outer planets

Uranus remains in Pisces during February at magnitude 5.9. It is an evening object setting just before 11.30 pm on the 1st and just after 8.30 pm, 90 minutes after the Sun, on the 29th.

Neptune, in Aquarius, sets about 70 minutes after the Sun on February 1. It is at conjunction with the Sun on the 29th. At conjunction Neptune will be half a degree south of the Sun as seen from Earth. The planet will then be 4.63 billion km, 30.95 AU, from Earth and 29.95 AU beyond the Sun.

Pluto continues to be in Sagittarius throughout February at magnitude 14.4. It is close to Mercury at the beginning of the month, the two separated by just over half a degree on the 1st. Five nights later Venus will be just over 1 degree from Pluto. These close approached will occur close to the star pi Sgr, magnitude 2.9. Pluto is less than 6 arc-minutes from the star on the 14th. At magnitude 14.4 a moderate telescope is needed to see, or image, the dwarf planet. Low altitude and dawn twilight will make this very difficult.

A better chance of finding Pluto close by pi Sgr will occur in June when Pluto's retrograde motion takes it less than 3 arc minutes from the star.

BRIGHTER ASTEROIDS: (1) Ceres is in Aquarius during February but getting close to the Sun. By the 29th the two will be only 8 degrees apart.

(4) Vesta, magnitude 8.3, starts February in Cetus. On the 1st, Vesta will set just before midnight. Early in the month the asteroid is just over 5 degrees from Uranus. On the 12th Vesta joins Uranus in Pisces but their distance apart will gradually increase. By February 29 Vesta will set about 10.20 pm.

(5) Astraea. This 125 km diameter asteroid is in Leo and starts February at magnitude 9.3. On the 1st it will rise at 9.19 pm at Wellington. The asteroid will then be just over half a degree above Regulus, mag 1.4, with no other star as bright as Astraea between the two. This will make finding Astraea fairly easy in the late evening.

Astraea is at opposition mid February with a magnitude 8.7. By then it will be some 3 degrees left of Regulus as seen late evening. At opposition it will be 2.086 AU from the Sun, very close to its perihelion, and 1.1 AU from Earth. The relatively close approach makes this a particularly favourable opposition for observation.

By the end of February, Astraea will be back to magnitude 9.3

Brian Loader  
New Zealand

The Solar System in January 2016

Dates and times shown are NZDT (UT + 13 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 January

                            January  1  NZDT                January 31  NZDT
                    morning  evening                 morning  evening
       SUN: rise:   5.48am,  set:  8.59pm    rise:   6.21am,  set:  8.45pm
Twilights
  Civil:    starts: 5.17am,  ends: 9.31pm    starts: 5.53am,  ends: 9.14pm
  Nautical: starts: 4.34am,  ends:10.14pm    starts: 5.15am,  ends: 9.52pm 
  Astro:    starts: 3.43am,  ends:11.04pm    starts: 3.33am,  ends:10.34pm

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

          Last quarter:  January  2 at  6.30 pm (05:30 UT)
  New moon:      January 10 at  2.30 pm (01:30 UT)
  First quarter: January 17 at 12.26 pm (Jan 16, 23:26 UT) 
  Full moon:     January 24 at  2.46 pm (01:46 UT)

The Earth is at perihelion on January 3 at noon NZDT (Jan 2, 23 hrs UT). It will then be 147 million km from the Sun (0.9833 AU).

The planets in January

At the beginning of January only Mercury of the naked-eye planets will be in the evening sky. But, at best, it will be very difficult to see. After conjunction mid month, Mercury joins the other four naked eye planets in the morning sky. The early evening sky will then be bereft of naked eye planets. By the end of January, Jupiter will rise about 10.30 pm so be easily visible to the east by midnight.

Mercury starts January as an evening object setting some 80 minutes after the Sun. On the 1st its magnitude will be -0.3 but with an altitude only 3.5 degrees, 45 minutes after sunset, it will be a difficult object. The Sun will be 8 degrees below the horizon so the westerly sky will still be bright making the planet difficult to see.

During the next few days Mercury gets closer to the Sun, especially after it is stationary on January 5 when the planet will start moving to the west and so towards the easterly moving Sun. Inferior conjunction is on January 14 when Mercury will be just under 50 million km from the Sun with the Earth 100 million km further out.

After conjunction Mercury becomes a morning object rising shortly before the Sun. The planet's westerly movement will take it quite quickly further from the Sun making it visible in the dawn sky. It is again stationary on January 26 by which date its motion away from the Sun will have slowed. On the last morning of January Mercury will rise almost 2 hours before the Sun. An hour after it rises the planet will be 8 degrees above the horizon with Venus the same distance above and to its left. At magnitude 0.3 Mercury should be fairly easy to see especially with Venus to act as a guide. But this is at about 5.30 am.

Venus remains a morning object rising about 140 minutes before the Sun all month. It starts January in Scorpius but moves into Ophiuchus on the morning of the 6th. Venus moves into Sagittarius on the 21st. On January 8 Venus will be 6 deg from Antares and on the 30th 3 degrees from the 2.8 magnitude star lambda Sgr.

As it moves to the east through the stars, Venus will overtake Saturn on January 9. At their closest, at about 5 pm, the two planets will be just over 5 arc minutes apart, about 1/6th of the moon's diameter. From NZ on the 9th at 5 am the two planets will be just over half a degree apart with Venus to the left of Saturn. They will be a similar distance apart on the 10th but with Venus now on the right of Saturn.

The crescent moon is closest to the two planets on the morning of January 7 when it will be 5 degrees left of Venus and 7.5 degrees from Saturn. The following morning the moon as a thinner crescent will below and a little to the right of the planets.

Mars rises 4 hours before the Sun on January 1 and nearly 6 hours before it on the 31st. Mars will be considerably higher than Venus. The planet starts the month at magnitude 1.3 in Virgo, 6 degrees below Spica. On the 18th Mars moves into Libra where it ends month a little brighter, magnitude 0.8. The morning of the 31st finds Mars 1.5 degrees from the star alpha Lib, magnitude 2.73

The moon, 36% lit, is closest to Mars on the morning of the 4th. The moon will be 2.5 degrees to the left of Mars.

Jupiter starts January in Leo with the 65% lit moon less than a degree to its upper left. On the 1st Jupiter rises about 12.30 am, by the end of January it will rise just before 10.30 pm so becoming visible late evening.

The planet is stationary on the 9th so its position changes little during the month. It gets to within a quarter of a degree of the boundary of Leo with Virgo, but as it starts moving back to the west retreats from the latter constellation.

The moon, now 82% lit, returns to the vicinity of Jupiter towards the end of January. On the morning of the 28th the two will be close to 4 degrees apart just before sunrise. Later in the morning, well after they set, the two will be just over a degree apart

Saturn rises just under two hours before the Sun on January 1, over four hours before the Sun on the 31st. It is in Ophiuchus all month at magnitude 0.5. See the notes for Venus for further details.

Outer planets

Uranus remains in Pisces during January at magnitude 5.8 to 5.9. It is an evening object. By the end of January it will be setting about 11.30 pm.

Neptune is also an evening object throughout January, by the end of the month it will set at 10.00 pm. The planet, magnitude 7.9, is in Aquarius.

Pluto continues to be in Sagittarius throughout January at magnitude 14.4. It is at conjunction with the Sun on January 6, after which it becomes a morning object rising as much as 2 hours before the Sun by the 31st. At conjunction Pluto will be nearly 5.1 billion km, 34 AU from the Earth and just over 33 Au beyond the Sun.

BRIGHTER ASTEROIDS: (1) Ceres is an evening object setting just before midnight on the 1st. It starts January in Capricornus at magnitude 9.3; on the 15th it moves into Aquarius. By the 31st, when it sets at 10.18, Ceres will be just over 10 degrees from Neptune.

(4) Vesta is in Cetus during January. It fades a little during the month from magnitude 8.0 to 8.3. The asteroid will be 6 degrees from Uranus on the 31st when it will set just before midnight.

(15) Eunomia is an evening object in Pisces during January, its magnitude fading from 9.5 to 9.8. It sets just before 11 pm on the 31st.

(27) Euterpe starts January in Gemini at magnitude 8.8 and is in the sky almost the whole night. By the 31st it will be a magnitude fainter and sets by 3am. The asteroid moves into Taurus on January 6.

Brian Loader  
New Zealand