Lethbridge will soon feature Canada's largest scale model of the solar system.

The Lethbridge Astronomy Society came up with the idea, and city council approved the project this week.

Tom Anderson, president of the society, told the Calgary Homestretch that the dome will act as the imaginary sun and the centre of the system.

A few blocks down the street, there will be a pedestal with a scale model of Mercury — at three quarters of an inch in diameter, it will be in scale with the diameter of the sun.

The whole point, Anderson said, is to show how big the sun is and how small the planets are.

Earth, for example, will be the size of a tennis ball in relation the the size of the "sun". Mars will be inside city limits. Neptune, the furthest planet, will be about 10 kilometres outside city limits.

"The idea is to build a scale model of the solar system in the middle of Lethbridge, and what we're going to be doing is modelling it after the size of the dome," Anderson said. "So we have this heritage building that was built in 1913. It's got this big clock tower on it, and there's a dome on the top which is 5.5 metres in diameter.

"If we imagine that to be the sun, then we can calculate the size to scale of each of the planets, and where their orbits would be."

There will be a brochure and an app to explain the whole installation.

"It's going to unfold throughout the city, and part of it's going to be in Lethbridge county because the solar system is a really big place," Anderson said. "And that's the point of the whole exercise, is to give people a more real experience of how vast just our little corner of the universe is."

Neptune will be in a provincial park called Park Lake, about 20 kilometres away from the sun model.

"So those are the kind of distances that we're talking about — 5.5 metres for the sun, and you've got to go 20 kilometres to get to the edge of the solar system."

The planets themselves will be sitting on pedestals, and each will be to scale. Earth, for example, will be about the size of a tennis ball.

The budget is between $30,000 to $40,000 for the project. Funding has been secured through a number of community partners, Anderson said.

"Everybody we've talked to has been very excited," Anderson said. "You know it really sparks the imagination and that's the whole point."

Anderson said the project will be a boon for the whole city, not just people who are into science.

"If you were going to do a walking tour of just the inner planets — and by that I mean Mercury, Venus, Earth and Mars — you could probably do that in half an hour to an hour depending on how long you linger at each location," he said.

"We could probably set up a pretty nice little marathon run. There are all kinds of spinoffs here."

Anderson said he also expects the solar system to be a real tourist draw.

"This is going to be the biggest one in Canada," he said. "There's a number of these at various locations throughout the world. Sweden has a huge one. But in terms of the Canadian context, this is going to be the biggest one in Canada."

The Lethbridge Astronomy Society hopes to have the solar system installation in place by the end of next summer.