The enthusiasm of astronomers makes them build observatories at their own homes. Tonight Patrick Moore looks at three home-built observatories, including his own, which he has successfully transferred to Northern Ireland. Not all are built for the same purposes.

Leap Year makes this a special month-but variations in earthly calendars are slight compared with those in other worlds. In tonight's programme, Patrick Moore talks about Uranus's 65,000-day year, Jupiter's 'year', twelve times as long as ours but with a 'day' of less than ten hours, and Venus's 'year', which seems shorter than its 'day'.

The Armagh Planetarium-the first big public planetarium to be built in Britain outside the London area-was opened to visitors on February 5. Its Director, Patrick Moore, shows viewers round and describes its principles and uses.

Patrick Moore discusses with Iain Nicolson the sooty clouds in space which hide some stars and themselves shine in the light from others.

Patrick Moore discusses with Michael Bentine the problems of manned flight beyond the Moon to the planets and stars. They examine the techniques devised in fiction and in fact to solve some of these problems.

In three weeks' time the asteroid Icarus, first seen in 1949, orbits close to the Earth. Patrick Moore talks to Dr. Vinicio Barocas about the nature and movements of the asteroids.

Sunspots, or 'storms' on the sun's surface, appear in maximum numbers about every eleven years; and large numbers are expected this year. Patrick Moore discusses with William Baxter the significance of sunspot activity.

Strange, quickly vibrating radio sources have been discovered far out in space. These pulsating stars or 'pulsars' are one of the most exciting discoveries of modern science, and have taken astronomers by surprise. Patrick Moore talks about them with Dr. A. Hewish at Cambridge and discusses the implications with Sir Bernard Lovell and Professor F. Graham Smith at Jodrell Bank.

Within a few months from now, man may land on the moon. Patrick Moore discusses with a geologist, Dr. Peter Cattermole, the conditions the first lunar astronauts are likely to find.

On September 22 a total eclipse of the sun will be visible in Russia. Patrick Moore explains why eclipses are scientifically important and what people in Britain will see.

Patrick Moore shows film and gives a first-hand description of the recent total eclipse of the sun he saw in Siberia, and discusses its scientific significance with another British astronomer who was there, Dr. Ron Maddison.

Radio-astronomers at Jodrell Bank are carrying out a series of remarkable experiments to measure the distance from earth of 'pulsars'-the mysterious regularly-ticking radio sources out in space which were discovered last year by British scientists. Patrick Moore discusses the significance of these experiments with Dr. Gerhard de Jager at Jodrell Bank

The planet Venus is like the earth in size, yet totally unlike it - as recent American and Russian probes have shown - in being an inferno of heat and clouds. Patrick Moore explains why modern research into Venus has only made the planet more mysterious than ever: and discusses with Commander Henry Hatfield, R.N., his remarkable photographs of the planets and the moon.

Is it unlucky to see the new moon through glass? The moon has always been thought to have a powerful influence on the earth, causing not only tides but good luck, bad luck, and even lunacy, according to its phases. Patrick Moore discusses with Henry Brinton, Bert Foord, weather man and J. P. Hutchinson, a psychiatrist the scientific truths and popular superstitions about the moon's effects on the earth.