The team's goal was to scan the sky for evidence of a massive ninth planet in the outer solar system.
One of the new moons in the outer group is particularly unique, according to astronomer Scott Sheppard at the Carnegie Institution for Science, who led the team that first spotted the moons previous year.
It's easy to understand why these 12 new additions had been missed so far. The telescope in Chile, with a powerful digital camera that can shade against glare and scattered light, provided Sheppard and his collaborators with a wider and more detailed view than had been possible before.
Using the Blanco four-metre telescope at Cerro Tololo Inter-American in Chile - which had been recently fitted with a new and highly sensitive instrument called the "Dark Energy Camera", which is about the size of a small auto - they detected objects that seemed to be moving against the background stars.
"Understanding these moons helps us understand what the planets were originally made from", Sheppard told ABC News via email, adding that the moons are "likely half ice and half rock". The team of astronomers, which in 2014 discovered the furthest known object orbiting the sun, had been looking for other objects on the fringe of our solar system.
Astronomers say they've discovered another 12 moons orbiting Jupiter.
The real oddity of this discovery is the twelfth new moon, which has been described as a real "oddball" for a number of reasons.
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The two others are among a closer, inner group that orbit in the prograde, or same direction. With technology advancing at the rate it is, we are on the cusp of a major breakthrough in human space exploration, and taking the next step towards a better understanding of the last frontier.
Most of the newly discovered moons orbit opposite to Jupiter's spin, what's known as a retrograde orbit.
SHEPPARD: They're going around the planet in the opposite direction that Jupiter rotates.
SHEPPARD: They didn't form with Jupiter.
Dubbed Valetudo, after the goddess of health and hygiene, great-granddaughter of the Roman god Jupiter, this peculiar object orbits the planet in a year and a half and seems to have an intriguing history. They take a little less than a year to orbit the gas giant. While the retrograde moons orbit in a clockwise direction, Valetudo travels in a counter-clockwise direction.
Nine of the 10 new moons orbit in a retrograde direction, that is, opposite direction of Jupiter's spin. "And that makes it a very unstable situation". "Head-on collisions would quickly break apart and grind the objects down to dust", Dr. Sheppard said.
One moon in particular caught the researchers' attention. They're thought to have formed after the gas and dust from the earliest stages of planetary formation had dissipated.
Overall, this was a tough, but very rewarding discovery.
But in the images, taken by the telescope in Chile, they did spot 12 new points of light in the vicinity of Jupiter.
Dr Gareth Williams, of the International Astronomical Union's Minor Planet Centre, Cambridge, Massachusetts, used the team's observations to calculate orbits for the newly found moons.