The Moon is at first quarter on the 6th, full on the 14th, at last quarter on the 22nd and new on the 29th. In fact, when the Moon is full and new this month there are eclipses that are both visible from Scotland. The first event occurs around midnight on the 14th/15th when the full Moon skims through the northern fringe of the Earth's shadow. The resulting penumbral eclipse lasts from 21:22 until 02:13 GMT, but little dimming of the Moon may result, except around its southern parts for a few minutes around mid-eclipse at 23:47.

Of much greater interest is the solar eclipse on the 29th, which is total along a line that stretches from the coast of Brazil, across western and northern Africa and Turkey, to end in northern Mongolia. The longest spell of totality, when the Sun's brilliant disk is fully hidden by the Moon, is 4 minutes 7 seconds as seen from the Libyan desert, about 20 seconds longer than for the many observers who have chosen Turkey as their vantage point. Observers in Europe enjoy a partial eclipse which, for London, lasts from 10:45 to 12:22 BST and sees the Moon's black outline extend across 28 per cent of the Sun's diameter at 11:33.

In Scotland we see a shallower event that starts a little later, ends earlier and takes a smaller bite out of bottom part of the Sun. For Edinburgh the eclipse begins at 10:55, sees 20 per cent of the Sun's diameter covered at 11:35, and ends at 12:16. Add three minutes to these times to get the circumstances for Aberdeen, while the corresponding details for some other locations around the country are: Glasgow 10:55, 11:34 (18 per cent), 12:14; Inverness 10:59, 11:36 (17 per cent), 12:15; Kirkwall 11:02, 11:39 (17 per cent), 12:17; Stornoway 11:01, 11:35 (15 per cent), 12:11.

To avoid serious eye damage, never observe the Sun directly through binoculars or a telescope. Instead, use so-called eclipse glasses, provided they are undamaged, or project the Sun's image onto a card through a pinhole, one side of a pair of binoculars or a small telescope. Projection through binoculars or a telescope is also good for seeing sunspots, but few of these are around at present while the Sun is nearing the minimum of its 11-year cycle of activity.

By our map times, Orion is sinking towards the west as the leading constellation in our spring sky, Leo, lies in the south. The lion's head and mane is represented by the Sickle and his heart by Regulus, a name that means "little king" in Latin and refers to the star's royal status since antiquity. Regulus lies 77 light years (ly) away and burns white-hot with the power of 130 Suns.

Telescopes show Algieba in the Sickle to be an excellent double star. At 125 ly, it consists of a pair of yellow-orange stars that turn about their shared centre of gravity every 600 years or so. A 12 Sun-power star at 36 ly, Denebola, the lion's tail, resembles Vega and the southern star Fomalhaut in being surrounded by a disk-like cloud of dust, possibly a planetary system in the making.

Between Leo and Gemini lies Cancer the Crab whose dim stars are overwhelmed by the golden light of Saturn at present. The planet reached opposition in late January and fades slightly this month from magnitude -0.1 to 0.1. However, it is still well placed as it climbs through the south-eastern sky during the evening to pass due south one hour before our map times. Binoculars reveal the Praesepe or Beehive star cluster alongside Saturn, while telescopes show the planet's disk and rings, which are 20 and 45 arcseconds wide respectively when the Moon lies nearby on the night of the 10th. Two nights later, the Moon passes even closer to Regulus.

Mars lies 5° to the left of the Pleiades In Taurus high in the south-south-west at nightfall this evening, shining brightly at magnitude 0.7. Find it low in the west at our star map times as it moves to set in the north-west more than three hours later. Of similar brightness and colour, and 9° below-left of Mars, is Aldebaran, the eye of Taurus. Mars fades to magnitude 1.2 as it recedes and tracks eastwards to pass north of Aldebaran on the 9th and end the period between the Bull's long horns. Telescopes now show little detail on the planet because its disk is shrinking below 7 arcseconds in diameter. The Moon lies between Mars and the Pleiades next Sunday night while NASA's Mars Reconnaissance Orbiter is due to reach the planet on the 10th.

As it nears the end of its best evening spell this year, there is just time to glimpse Mercury very low in the west after sunset. Forty minutes after sunset on Wednesday, binoculars may show it shining at magnitude 0.8 and standing 8° high and 9° below-right of the thin sliver of the virgin Moon. Expect to lose it during the coming week as it moves towards inferior conjunction on the Sun's near side on the 12th.

Both Venus and Jupiter are conspicuous morning objects. Jupiter, in fact, rises at Edinburgh's east-south-eastern horizon at 00:22 GMT on the 1st and by 22:14 GMT (23:14 BST) on the 31st, and is unmistakable 15° high and a little to the west of south before dawn. It improves from magnitude -2.4 to -2.6 this month and shows a sizeable 42 arcseconds disk through a telescope when it stands 6° above-left of the Moon before sunrise on the 19th. Venus is a dazzling -4.6 morning star low in the south-east for two hours before sunrise at present, fading a little to magnitude -4.3 by the 31st when it rises only 70 minutes before the Sun.

Brown's 2003 book has sold more than 30 million copies worldwide and earned the American 45 million pounds (66 million euros, 78.5 million dollars) in one year, instantly making the writer one of the world's richest.

Baigent's and Leigh's book tackles theories that Jesus and Mary Magdalene married, had a child, and the blood line continues to the present day -- with the Catholic Church aware of the discovery and trying to suppress it.

A third author, Henry Lincoln, is not part of the lawsuit.

Brown's book, which combines thriller, detective and conspiracy theory genres, explores similar themes about the Vatican covering up the true story of Jesus.

The novel has been translated into 44 languages and drawn criticism from the Roman Catholic Church and historians.

If Baigent and Leigh are successful and obtain injunctions preventing the use of their material it could threaten the British release of the film adaptation of "The Da Vinci Code".

The big screen version, costing 100 million dollars and starring American two-time Oscar winner Tom Hanks, British veteran actor Sir Ian McKellen and French favourites Audrey Tatou and Jean Reno, is scheduled to open in Britain on May 19.

The case is expected to last up to two weeks, barring a settlement. It is also likely to clarify the extent to which an author can use other people's research under existing copyright laws.

Brown acknowledges the theories of "Holy Blood, Holy Grail" in his novel. The villain is called Sir Leigh Teabing, which bears a remarkable resemblance to Baigent and Leigh's surnames.

Science is not cold and remote in this setting. It's live, interactive, free and informal, with a drink or two. And other Cafe Scientifique meetings are popping up throughout the country and around the globe on campuses, in coffee shops, bars and even a church. The purpose is to make science accessible and even fun to anyone with the time to stop by.

"A lot of people come to see real, live scientists--some of whom are extremely famous and prominent--and see how their brains work," said Dr. John Cohen, a professor of immunology at the University of Colorado Health Sciences Center and the founder of the Denver Cafe Scientifique. "People don't often get a chance to do that. Some come to ask questions, others are content to listen."

The Denver Cafe Scientifique was established in 2003 and is the largest in the country to date, drawing about 150 people. The topics vary from sleep to interstellar communication to Higgs bosons to nanotechnology, and they attract people of all ages and occupations.

"Who would have thought you'd have standing room only at a geek event?" Cohen asked. He said he first read about science cafes in 1999 when they were catching on in England. "It just sounded like so much fun," he said. "I saw it as a reminder of the peripatetic philosophers who wandered the Agora in Athens." He imagined them, he continued, "stopping every so often to refresh themselves with a mug of wine from the local sellers."

It was an article by Duncan Dallas in the scientific journal Nature that inspired Cohen and others. Dallas, now a retired television producer, started Cafe Scientifique in 1998 with a note posted in a bar in Leeds, England, that said: "Where, for the price of a cup of coffee or a glass of wine, anyone can come to discuss the scientific ideas and developments which are changing our lives."

He said he was inspired by French philosophy clubs; coincidentally, science cafes were starting up in France in the late 1990s. In an e-mail message, Dallas said that taking science out of the classrooms changes the expectations of the audience and the speaker--from lecturing to discussing.

"I believe that science is the most important force in our culture," Dallas wrote, "and is increasingly impinging on our public and personal lives, through subjects like genetics, neurology, pharmacology and evolutionary psychology. So public engagement with science is bound to increase in many forms over the next decade."

Cafe Scientifiques in Britain received public financing to get started, and dozens are now held around the country. In the United States some such cafes have no budgets and are independent--like the one in Denver--while others receive school and corporate help.

Two science cafes in New York--one in Syracuse and the other in New York City--break from the tradition of free science to all and charge $5 to $10.

Sigma Xi, a scientific research society, was host to the first national gathering of Cafe Scientifique leaders this month in North Carolina to network and organize the movement.

Juliana Gallin, a 38-year-old graphic designer in San Francisco, started "Ask a Scientist" at the Bazaar Cafe two and a half years ago. "I was trying to think of something interesting to do outside of my day job that would be more personally fulfilling than the typical volunteer opportunities I was encountering," Gallin said, noting that it was only later that she learned of the Cafe Scientifique movement.

In Seattle, Gretchen Meller, a research scientist, and a few of her friends had their first event last September in a local bookstore. "If the general population is to vote on these issues eventually," she said, "they need the opportunity to ask questions."

Indeed the topics are sometimes taken from headlines. Cafe Scientifique Pittsburgh will be host to the author Pamela Winnick, who will discuss her book "A Jealous God: Science's Crusade Against Religion." The Pittsburgh science cafe was started by two science writers in 2004 and is held at the Penn Brewery every month. Tim Palucka, a 46-year-old freelance science writer, shows off the humorous side of Cafe Scientifique when he jokes that their motto should have been "Talk to a drunk scientist" instead of "Eat. Drink. Talk Science."

The topics are not always so funny. Tony Cox spoke here recently on "Risk Analysis and Public Health." Sipping on their microbrews, people listened and then rushed up to Cox to ask questions during a break before the official questions and answers began.

"It's almost like continuing education," said Lyda Ludeman, a 64-year-old retired IBM systems controller. "And the great part is, they don't test you." Ludeman comes to Cafe Scientifique every month with a group of regulars, some wearing denim shirts with Cafe Scientifique logos sewn on the chest.

John Farmer, a 49-year-old advertising executive who attended with his girlfriend last month, said he liked to come to Cafe Scientifique occasionally to learn about different topics. "A lot of people are intimidated by science," he said. "It's great to drink a beer and to brush elbows with these geeks who have very disciplined minds. Everybody can use a little more science in their lives."

Butler's work wasn't preoccupied with robots and ray guns, Howle said, but used the genre's artistic freedom to explore race, poverty, politics, religion and human nature.

"She stands alone for what she did," Howle said. "She was such a beacon and a light in that way."

Jane Jewell, executive director of the Science Fiction and Fantasy Writers of America, said Butler was one of the first black women to explore the genre and the most prominent. But Butler would have been a major writer of science fiction regardless of race or gender, she said.

"She is a world-class science fiction writer in her own right," Jewell said. "She was one of the first and one of the best to discuss gender and race in science fiction."

Butler began writing at age 10, and told Howle she embraced science fiction after seeing a schlocky B-movie called "Devil Girl from Mars" and thought, "I can write a better story than that." In 1970, she took a bus from her hometown of Pasadena, Calif., to attend a fantasy writers workshop in East Lansing, Mich.

Her first novel, "Kindred," in 1979, featured a black woman who travels back in time to the South to save a white man. She went on to write about a dozen books, plus numerous essays and short stories. Her most recent work, "Fledgling," an examination of the "Dracula" legend, was published last fall.

She received many awards, and in 1995 Butler was the first science fiction writer granted a "genius" award from the John D. and Catherine T. MacArthur Foundation, which paid $295,000 over five years.

Butler described herself as a happy hermit, and never married.

"Mostly she just loved sitting down and writing," Seattle-based science fiction writer Greg Bear said. "For being a black female growing up in Los Angeles in the '60s, she was attracted to science fiction for the same reasons I was: It liberated her. She had a far-ranging imagination, and she was a treasure in our community."