SkyEye

The Calendar

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 Leo → Virgo

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

Mercury Leo → Virgo

Now a morning sky object, Mercury rises quickly early in the month and then sinks back down just as fast from a northern vantage point. For southern observers, the closest planet to the Sun remains low in the east before sunrise all month. On 12 September, Mercury reaches greatest elongation west and six days later it is the last of four bright objects (three planets and one star) to be occulted by the Moon.

Venus Cancer → Leo

The morning star is best seen from northern latitudes this month, high above the eastern horizon before sunrise. It is much lower in the sky as viewed from the southern hemisphere and is slowly losing altitude. Beginning around 22:00 UT on 17 September, Venus is occulted by the Moon as seen from the Indian Ocean.

Mars Leo

Mars emerges from the morning twilight around mid-month. Along with Mercury and Venus, the red planet is occulted by the Moon on 17/18 September.

Jupiter Virgo

Jupiter is getting increasingly difficult to observe as it heads towards conjunction next month.

Saturn Ophiuchus

Saturn will be a east quadrature on 14 September. This is an excellent time to observe and photograph the planet as the shadows of the planet's disc, rings and moons are all cast maximally off to one side, lending an interesting three-dimensional effect to the scene. It is best observed from southern latitudes where it doesn't set until late evening. The following day at 10:44 UT, the spacecraft Cassini will plunge into Saturn's atmosphere. Launched on 15 October 1997 from Cape Canaveral Air Force Station in Florida, the spacecraft spent 13 years orbiting Saturn, far exceeding its original four-year mission plan. The data returned by Cassini has revolutionised our understanding of Saturn, its ring and its moons. Farewell, Cassini!

Uranus Pisces

Uranus rises in mid-evening and is getting ever brighter as it approaches opposition next month.

Neptune Aquarius

A small telescope is necessary to view the most distant planet in the solar system. Opposition is on the fifth day of the month so this blue ice giant is aloft most of the night. The southern regions of South America (and parts of Antarctica) may see this planet occulted by the Moon on the following day.