Dates and times shown are NZDT (UT + 13 hours) Rise and Set times are for Wellington. They will vary by a few minutes elsewhere in NZ. Data is adapted from that shown by GUIDE 9.


THE SUN and PLANETS in JANUARY 2019, Rise & Set,  Mag. & Cons.
      January  1    NZDT           January 31    NZDT  
      Mag  Cons    Rise    Set     Mag  Cons    Rise    Set
SUN  -26.7  Sgr   5.48am  8.59pm  -26.7  Cap   6.22am  8.45pm
Merc  -0.4  Oph   4.39am  7.51pm   -1.5  Cap   6.20am  8.57pm
Venus -4.6  Lib   3.05am  5.09pm   -4.3  Oph   2.58am  5.47pm
Mars  -0.5  Psc  12.33pm 12.44am   .0.9  Psc  12.18pm 11.30pm
Jup   -1.8  Oph   3.51am  6.44pm   -1.9  Oph   2.15am  5.14pm
Sat    0.5  Sgr   5.58am  8.58pm    0.6  Sgr   4.13am  7.10pm
Uran   5.8  Psc   2.58pm  1.52am    5.8  Psc   1.01pm 11.55pm
Nep    7.9  Aqr  11.11am 12.11am    8.0  Aqr   9.18am 10.15pm
Pluto 14.5  Sgr   5.40am  9.36pm   14.5  Sgr   4.43am  7.38pm

             January  1  NZDT          January 30  NZDT
Twilights    morning     evening        morning     evening
Civil:    start 5.17am, end  9.31pm   start 5.54am, end  9.14pm
Nautical: start 4.34am, end 10.14pm   start 5.15am, end  9.52pm
Astro:    start 3.43am, end 11.04pm   start 4.33am, end 10.34pm

  New moon:      January  6 at  2.28pm (01:28 UT)
  First quarter: January 14 at  7.45pm (06:45 UT)
  Full Moon:     January 21 at  6.16pm (05:16 UT)
  Last quarter   January 28 at 10.10am (Jan 27, 21:10 UT)

The Earth is at perihelion on January 3 at about 7pm. At its closest it will be 147 million km, 0.983 AU, from the Sun

Eclipses of both the Sun and Moon occur during January. Neither is visible from New Zealand.

The partial eclipse of the Sun on January 6 is visible from eastern China, Korea, Japan and northeast Siberia

All stages of the total eclipse of the Moon on January 21 are visible from North and South America. The earlier stages are visible from western Europe and Africa.

EROS will be an interesting asteroid to look for towards the end of January. It will be visible in the evening sky.


PLANETS in January 2019.

MERCURY rises just over an hour before the Sun on the 1st close to the time of the start of nautical twilight. It is likely to be too low to observe before the sky becomes too bright. During the month the interval between Mercury and Sun rise decreases until the planet is at superior conjunction on the 30th.

At conjunction, Mercury will be 63.5 million km, 0.424 AU, beyond the Sun and 210.5 million km from the Earth

VENUS, as a morning object, reaches its greatest elongation, 47° west of the Sun on January 6. It will then rise nearly 3 hours before the Sun, so be an easy object before sunrise. On the 2nd the crescent moon will be within 1.2° of Venus a little before midday. Shortly before sunrise the two will be about 3.3° apart. See also the asteroid Ceres which will be close to Venus.

Venus starts January in Libra, crosses a narrow portion of Scorpius between January 9 and 14, after which it moves through Ophiuchus to end the month on the boundary of Sagittarius. In the process Venus overtakes Jupiter, the two being 2.4° apart at their closest on the morning of the 23rd.

MARS is in Pisces all January and continues to be an evening object, although getting lower in the west. By the end of January it sets at 11.30pm. It also fades considerably as the Earth swings away from the planet. Gone is its opposition brightness rivalling Jupiter.

The moon passes Mars on the 13th. At 10pm the moon, less than a day before first quarter, will be just under 6° from the planet.

JUPITER, in Ophiuchus all month, starts January some 5.5° from Antares. Their separation increases to nearly 10° by the 31st. Venus passes the slower moving Jupiter on the morning of January 23. The waning, crescent Moon is 6° from Jupiter on the morning of January 4, as seen from NZ. A second close approach occurs on the morning of the 31st with the moon just over 5° from Jupiter.

SATURN is at conjunction with the Sun on January 2. At conjunction the planet will be only 12 arc-minutes north of the Sun’s limb. In fact the planet will be just over 10AU, 1.5 billion km beyond the Sun.

After conjunction, Saturn becomes a morning object in Sagittarius, by the end of January it rises just over 2 hours before the Sun.

URANUS, is an evening object setting close to midnight on the 31st. It is stationary on the 7th, so will be moving very slowly in Pisces close to a corner of Aries. On the evening of January 14, the moon, at first quarter, will be just under 5° from Uranus.

NEPTUNE is an early evening object in Aquarius setting about 10.15 pm by the 31st. On January 11 the planet will be a little over 4° from the crescent moon.

PLUTO is at conjunction with the Sun on January 11. At this conjunction the Sun will pass in front of Pluto, “hiding” the planet for about 11 hours. Pluto will be just over 5 billion km (33.7 AU) beyond the Sun.


BRIGHTEST ASTEROIDS in JANUARY, magnitude, constellation, time of transit


               JANUARY 1   NZDT      JANUARY 31  NZDT  
               Mag  Cons  transit    Mag  Cons  transit
(1)  Ceres     8.9   Lib   9.58am    8.8   Sco   8.42am
(2)  Pallas    9.0   Vir   8.00am    8.7   Vir   6.36am
(3)  Juno      8.2   Eri  10.13pm    8.9   Tau   8.33pm
(4)  Vesta     8.1   Cap   3.52pm    8.1   Aqr   2.53pm
(6)  Hebe      8.5   Ori  12.57am    9.2   Ori  10.38pm
(433)Eros      9.2   Per  10.53pm*   9.4   Tau   9.50pm
(532)Herculina 9.6   Leo   4.31am    9.0   Leo   2.20am

 *Eros is only visible from the northern half of N. Island at first.

CERES is in Libra until the last day of January when it moves into Scorpius. On the 1st it rises at 3.11 am. On the morning of January 2 the moon will be 49 arc-minutes above Ceres at about 4am.. Also Venus will be about 4° to the right of the two. By the end of January, Ceres will rise at 1.45 am.

PALLAS, also a morning object, rises before Ceres, at 1.35 am on the 1st and 12.24 am on the 31st. It is in Virgo and is just over 5° from Spica at the start of the year.

JUNO is an evening object. It sets at 4.25 am on the 1st, two hours earlier on the 31st. It starts January in Eridanus but moves on into Taurus on January 8.

VESTA, is an evening object, setting at 11.15 pm on the 1st and just before 10 pm on the 31st. Starting January in Capricornus, the asteroid moves into Aquarius on the 24th.

HEBE rises before sunset at 7.14 pm on the 1st a On the 31st it sets just after 4 am. The asteroid is in Orion near Betelgeuse. On the 20th Hebe will be a little over 2° below the star at 9 pm.

EROS starts January with a declination more than 50°N, so will then only rise for places north of about New Plymouth in New Zealand. But it will be moving almost due south gaining nearly a degree a day. By mid month Eros will rise throughout NZ. It will transit and so be highest around 10 pm NZDT. On the 19th the asteroid will reach an altitude 13° at Wellington, with a magnitude 9.1. It will then be in Auriga.

On the 27th, Eros moves into Taurus and will be about 6° to the left of El Nath, beta Tau at 10pm. It will be moving at 2.5 arc-minutes per hour in PA 151° so its change in position will be telescopically detectable in a few minutes.

By the end of January Eros’ maximum altitude will be 23.6° at Wellington, magnitude 9.3. Eros will then be 0.22 AU, 33 million km from the Earth.

Eros was the first near Earth asteroid to be discovered, on 13 August 1898 by G. Witt at Berlin Observatory. In the first part of the 20th century, close approaches of the asteroid to Earth were used to determine the solar parallax and hence the Astronomical Unit, the 1930/31 determination being the best determination of the AU before the use of radar.

Eros was visited by the NASA Shoemaker spacecraft in 2000 and 2001. It is an elongated object, about 34km in length and a transverse diameter 11 km.

HERCULINA has a diameter of some 230 km, so is far larger than Eros. The asteroid is in Leo. It rises just before midnight on the 1st and at about 10 pm on the 31st. It will be a fairly low object for NZ, getting lower as the month progresses.

Brian Loader