JANUARY 2019

Mercury rose just over an hour before the Sun on January 1, close to the time of the start of nautical twilight.

That makes it too low to observe before the sky becomes too bright.

During the month the interval between Mercury and sunrise decreases until the planet is at superior conjunction on January 30.

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 degrees west of the Sun on January 6. It will then rise nearly three hours before the Sun, making it an easy object before sunrise.

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 degrees apart at their closest on the morning of January 23.

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 January 13. At 10pm the Moon, less than a day before first quarter, will be just less than 6 degrees from the planet.

Jupiter, in Ophiuchus all month, starts January some 5.5 degrees from the star Antares.

Their separation increases to nearly 10 degrees by January 31.

Venus passes the slower moving Jupiter on the morning of January 23.

The waning, crescent Moon was 6 degrees from Jupiter on the morning of January 4, as seen from NZ.

A second close approach occurs on the morning of January 31 with the Moon just over 5 degrees from Jupiter.

Saturn was at conjunction with the

Sun on January 2.

At conjunction the planet appeared to be only 12 arc-minutes north of the Sun’s limb. In fact the planet was 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 two hours before the Sun.

NASA’s New Horizons probe has made contact with Earth to confirm its successful flyby of the icy world known as Ultima Thule.

The encounter occurred some 6.5 billion kilometres away, making it the most distant ever exploration of an object in our solar system.

The radio message from the robotic craft took six hours and eight minutes to traverse the huge expanse of space between Ultima and Earth. Ultima is located in the Kuiper belt, a band of frozen material that orbits the Sun more than 2 billion km further out than Neptune; and 1.5 billion km beyond the dwarf planet Pluto that New Horizons visited in 2015.