March towards spring

WELCOME TO the March night sky. This is the month of the spring Equinox, when the path of the Sun crosses the celestial equator of the sky and enters the northern hemisphere. All this comes about due to the tilt of the Earth’s axis relative to the plane of its orbit.

From our point of view, and from a fixed point on the surface of our planet, the Sun can appear high in the sky at midday and, six months later, much lower at the same time. The difference is quite dramatic (more than 45 degrees) and, of course, we know the effects of this from the change in the seasons.

Now, at this time of year, the Earth is midway between the two extremes and the whole world receives equal amounts of day and night. This also implies that, on the exact Equinox day, the Sun rises precisely in the east and, 12 hours later, sets precisely in the west. This year the date is March 20. After that date it is officially spring in the northern hemisphere.

On March 29, there is a Solar Eclipse visible from Europe, but it is only partial, with 34 per cent of the Sun’s disk covered by the Moon. It will start at 9am and be over by 11am. You will, of course, require proper filters to view the Sun. A number 14-arc welder’s glass filter is the easiest to find.

The ringed planet Saturn is visible all night in the constellation of the Crab, and the moon will be close on the fifth. By midnight, the giant planet Jupiter rises and the moon will be close on the night of March 19.

The Full Moon on March 14 will not be as bright as normal as it will enter into the penumbral shadow of the Earth around midnight – this effect is slight and may not be noticed.

The Moon is at First Quarter on March 6, Full on March 14, Last Quarter on March 22 and New on March 29.

• Clive Jackson is the Director of the Astronomical Observatory of Tavira (Sitio do Malhão) and the Camera Obscura (next to the Castle in Tavira), specialising in education and public outreach.

Tel 281 321 754, Fax: 281 324 688,

e-mail: cdepa@mail.telepac.pt or

visit www.cdepa.org