This week the Scottish Chamber Orchestra closes its main season with The Creation: Joseph Haydn's resounding oratorio, a work so jubilant and life-affirming that the conductor Harry Christophers describes it as being "like one long wedding reception".

The Creation is "full of wit and full of joy," he says; "there aren't many piece whose music just smiles the whole way through."

There has been some healthy speculation over the inspiration behind Haydn's blithe-spirited masterpiece. One theory, touted in a 1950 Haydn biography by HE Jacob, suggests that when the composer looked through a telescope belonging to the astronomer William Herschel he was so overwhelmed by the magisterial night sky that he vowed to pen a great choral paean in honour of God's creations. It is certainly true Haydn took a peek through that telescope - his diary recounts the trip to visit Herschel in Slough in 1792 - but whether that was the seed for The Creation is pure conjecture.

A more accepted version of events pinpoints a vast performance of the Messiah in London in 1971, when a choir of hundreds and a mammoth orchestra blasted Handel's music around Westminster Abbey. Several years later, armed with an English translation of Genesis and Milton's Paradise Lost, Haydn devoted almost 12 months to crafting The Creation - and this from the composer of 106 symphonies who dashed off scores at eye-watering speeds. Whatever spurred him on to write The Creation, he wanted to be magnificent, and after the wild success of its premieres he did modestly acknowledge his achievements. "Often," he wrote, "when I was struggling with all kinds of obstacles ... a secret voice whispered to me: 'There are so few happy and contented people in this world; sorrow and grief follow them everywhere; perhaps your labour will become a source from which the careworn ... will for a while derive peace and refreshment'."

For Christophers, as for most admirers of The Creation, it is Haydn's musical depiction of the natural world that makes the piece so exceptionally vivid. "Haydn was a better orchestrator than Mozart," Christophers offers, a little conspiratorially, and follows up the statement with example after example of Haydn's brilliant musical tricks, singing them cheerfully down the phone from his house in Kent.

There's the roaring lion, a jovial, dissonant roar from trombones and contrabassoon. There's the moment when whales are sombrely introduced by the violas and cellos, and of course there are the birds: soaring larks, eagles, nightingales and doves, cooing in gorgeous bassoons and flutes. The most famous part of The Creation is its opening minutes, a stunningly experimental representation of chaos in which catches of harmony and melody stumble about around as if in tonal freefall. Later we hear the sublime first sunrise and the gentle, mysterious moon. Christophers also points to Haydn's use of silence: "I often think you can tell a good composer by how he uses silence, and Haydn uses a whole lot of it. This piece isn't just Haydn as a masterful orchestrator, it is Haydn as a superb portrayer of image.The whole thing is really one big tone poem, with words."

And those words will be sung, in English, by a superb line-up of soloists: soprano Sophie Bevan, tenor Andrew Staples and baritone Matthew Brook (a regular with the Dunedin Consort), all of them unfussy, intelligent and expressively generous singers. "I'm sure they'll clinch the vividness of this text," says Christophers. "They'll have the audience really laughing at Haydn's fabulous word-painting."

When we speak Christophers is just back from performing The Creation with Boston's venerable Handel and Haydn Society, an institution founded in 1815 of which he has been music director since 2008. The H&H Society has a long history with The Creation - it performed the American premiere back in 1819 - and Christophers says the chance to get to know Haydn through such a deep heritage has been a great revelation over the past decade. "A lot of people regard Haydn as the grandfather of the symphony, which makes him sound a bit fuddy-duddy. I was probably in that camp until I started to really delve, then I began to appreciate just how cutting-edge his writing is."

Now Christophers is of the mind that all orchestras should play Haydn at least once a month (the SCO's recent seasons score highly in this regard). "His music is such good discipline, partly because of the limited musical instructions he gives his players. In The Creation the pages are littered with staccato markings, but these could mean so many different things. I would love to ask Haydn what he intended but I can't, and bringing them to nuanced life requires real engagement from every musician on stage. In romantic music we have instructions on basically every note. Here there has to be deep musical intuition in order to make it work."

The term "musical intuition" is a crucial one. As founding conductor of The Sixteen, a vocal group specialising in renaissance repertoire, Christophers has long been immersed in the study of ancient music, yet he renounces the kind of academic scholarship often associated with the early music movement. He has stated in interviews: "I hate analysis, I can't think of anything more boring," and he laughs when I raise the point. "I really do think you should just play the music!" he says. "Yes, Haydn wrote using certain forms, but that shouldn't mean we feel strapped into those forms. His music is so full of comedy and wit. It should be such fun." Later he clarifies that he does think a strong sense of musical architecture is important, "but that's the broader task of getting from A to B rather than getting bogged down in the details. I hate anything that sounds too academic."

A rejection of academic orthodoxy was the driving force behind The Sixteen's founding in the late 1970s. Christophers was determined to create an ensemble to sing early repertoire with sensuality and lavish expression rather than the sound associated with Oxbridge choral traditions. More than 35 years later, the group has paradoxically established new conventions of its own: the pristine, shapely lines of The Sixteen are iconic, and have spawned any number of imitation acts. But Christophers doesn't worry about creating a new status quo. "We cover such a range of repertoire that we keep what we do alive. Singing is always about the text, so we always dig into the words and that helps keep things fresh." �¨For the past 15 years, The Sixteen has been touring the UK's parish churches and cathedrals with its annual Choral Pilgrimmage. This year's Pilgrimage stops at St John's Kirk, Perth, with a programme exploring the sumptuous music of Spanish Renaissance composers Francisco Guerrero and Alonso Lobo. "What a great place it must have been to make music," says Christophers of 16th century Seville, describing Lobo's Versa est in luctum as "perhaps one of the greatest renaissance works, though it's known by only a select few. My God, it is beautiful. There is this amazing subtle dissonance at its heart - I mean, if you did it grossly it would be really very gross, but treat it right and it is sublime." I suspect The Sixteen will treat it right.

Harry Christophers conducts the Scottish Chamber Orchestra in Haydn's The Creation at the Usher Hall, Edinburgh, on Thursday and City Halls, Glasgow, on Friday. The Sixteen's Choral Pilgrimage is at Perth's St John's Kirk on May 26.