SkyEye

The Calendar

Spring comes to the northern hemisphere and autumn to the south when Earth reaches the vernal equinox on 20 March. The Moon continues to occult various planets, with Jupiter and Venus disappearing behind the lunar disk two days apart near the end of the month.

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 Capricornus → Aquarius → Pisces → Cetus → Pisces

Mercury has two encounters with superior planets early in the month, appearing half a degree south of Saturn on 2 March and 0.4° north of Neptune on 15 March. However, with superior conjunction only two days later, the conjunction with faint Neptune is unobservable. The tiny planet returns to the evening sky for what is the best western apparition of the year for northern temperate latitudes. The waxing crescent Moon, only a day past new, is 1.8° south of magnitude −1.8 Mercury on 22 March. Mercury has a rather closer encounter with Jupiter on 28 March when the two planets are 1.3° apart.

Venus Pisces → Aries

Venus continues its ascent in the west, with northern and equatorial regions getting the best views of the evening star. It is less than a degree north of Jupiter on the second day of the month. Ten days after passing through its ascending node on 14 March, it is occulted by the crescent Moon as seen from southeast Asia. On 30 March, bright Venus and faint Uranus are 1.2° apart in the evening twilight; a telescope will be necessary to spot Uranus. Look for the evening star in western skies after sunset.

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 waxing crescent Moon occults the two brightest planets in the solar system this month, Jupiter on 22 March and Venus two days later. It makes its usual journey past several bright stars as well, appearing 1.7° south of Pollux on 3 March, 1.6° north of Antares on 14 March, 1.9° south of M45, the Pleiades open star cluster, on 25 March, and finally 1.6° south of Pollux again on the penultimate day of the month.

Mars Taurus → Gemini

An evening sky object, Mars is best observed from the northern hemisphere where the ecliptic is well above the horizon before midnight. The red planet reaches east quadrature (90° from the Sun) on 16 March. Three days later it is at its maximum declination north for the year. There is no lunar occultation this month, with the waxing crescent Moon only coming to within 2.3° of the red planet on 28 March. Mars appears 1.2° north of the open cluster M35 on the same day.

Jupiter Pisces

With conjunction looming next month, Jupiter is getting increasingly difficult to spot low in the west after sunset. The nearby presence of Venus on 2 March and Mercury on 28 March is further proof of the Sun's proximity. A very young crescent Moon occults the gas giant around sunset on 22 March for observers in northeastern South America. The close approach of magnitude −2.0 Jupiter to the fourth-magnitude star ε Piscium on 26 March may be too low in the twilit skies to observe.

Saturn Aquarius

Like Mercury, which approaches to within 0.5° on the second day of the month, Saturn is a morning sky object. Its appearance in the east is best viewed from the southern hemisphere where Saturn rises an hour or more before the Sun. The waning crescent Moon passes 3.6° south of the first-magnitude planet on 19 March.

Uranus Aries

The series of lunar occultations that began last year has finished, with the waxing crescent Moon approaching to only 1.5° of the faint planet on 25 March. Uranus pairs with the brilliant evening star on the penultimate day of the month when the two planets are 1.2° apart. An evening sky object, Uranus is best seen from northern latitudes where it doesn't set until late evening. Choose a moonless night to look for this sixth-magnitude object.

Neptune Aquarius → Pisces

Neptune is at conjunction this month and not visible in the night sky.