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A distinctive pair of starlike objects is visible high above the
northwestern horizon. That on the right - having a somewhat yellowish
colour - is in fact the planet Saturn. Whilst it is no more than a
bright point to the naked eye and even binoculars, a small telescope
will reveal its wonderful ring system. In recent years, the Cassini
spacecraft, now in orbit around the ringed planet, has returned
wonderful close-up views (visit
http://saturn.jpl.nasa.gov). The other object is Regulus, the
brightest star in the constellation of Leo. Its apparent proximity to
Saturn is merely a line-of-sight effect. The light of Saturn takes
only about a hour and a quarter to reach Earth; the light of Regulus
takes 77 years, so what you see tonight is Regulus as it was in 1931!
The true luminosity of Regulus is about 130 times that of our Sun.
By contrast the brightest stars of the Southern Cross - seen high
above the southern horizon - are more than 300 'light years' out and
have luminosities about a thousand times greater than our Sun.
The Moon will be in the evening sky May 7 to 23.
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