SkyEye

The Calendar

Both Earth and Mars reach an equinox this month, and on both planets, spring will be coming to the northern hemisphere and autumn to southern latitudes.

The Solar System

The word planet is derived from the Greek word for 'wanderer'. Unlike the background stars, planets seem to move around the sky, keeping mostly to a narrow track called the ecliptic, the path of the Sun across the stars. Dwarf planets and small solar-system bodies, including comets, are not so constrained, often moving far above or below the ecliptic.

Sun Aquarius → Pisces

The solar south pole is most inclined toward the Earth early this month.

Mercury Pisces → Aquarius

Mercury is still visible after sunset to observers in northern temperate latitudes at the beginning of the month but it soon vanishes in the west as it approaches inferior conjunction on 15 March. Its reappearance in the morning sky is the best morning apparition this year for southern hemisphere viewers. Mercury temporarily enters into retrograde motion between 5 March and 27 March.

Venus Sagittarius → Capricornus → Aquarius

The morning star has another close encounter with the waning crescent Moon on 2 March when the two bodies are 1.2° apart. Venus rises as much as three hours ahead of the Sun when viewed from the southern hemisphere but this is a rather disappointing apparition for observers in northern temperate latitudes as Venus never rises very high in the east. However, greatest elongation west is long past and the bright planet is losing height above the eastern horizon little by little every morning.

Earth and Moon

Earth reaches the first of two equinoxes on 20 March. The word equinox means 'equal night' so that on this day, the (centre of the) Sun spends an equal amount of time above and below the horizon everywhere on the planet. The northern hemisphere greets the beginning of spring and the southern hemisphere welcomes the coming of autumn.

Mars Aries → Taurus

Now a first-magnitude celestial object, Mars continues its eastward trek across the background stars, remaining in direct motion for the entire year. An equinox comes to the red planet on 23 March when the northern hemisphere welcomes spring and the southern hemisphere enters Martian autumn. By the end of the month, Mars is found in the vicinity of M45, the Pleiades open cluster and is visible in the evening sky.

Jupiter Ophiuchus

West quadrature, occurring this year on 14 March, is always an interesting time to train a telescope on Jupiter. The shadows of the planet and its Galilean satellites are cast noticeably to one side, leading to some interesting views as the moons' shadows pass across the disk of the primary. The waning gibbous Moon passes within 2° of the gas giant on 27 March.

Saturn Sagittarius

Saturn is repeatedly occulted by the Moon this year and this event happens twice in March. On the first day of the month, the waning crescent Moon begins to pass in the front of Saturn on 16:00 UT. Later, on 29 March, Saturn again disappears behind the face of the Moon starting at around 02:30 UT. Saturn is a morning sky object and is best viewed from the southern hemisphere.

Uranus Aries

Uranus is approaching conjunction next month and may already be too faint to see in the sunset skies of the southern hemisphere. However, observers in northern temperate latitudes may still be able to observe this sixth-magnitude planet before it sets mid-evening.

Neptune Aquarius

Neptune is at conjunction on 7 March and is lost to view in the glare of the Sun. Its conjunction with Mercury on 24 March is likely unobservable.