There is a new star in our midst. And the only reason we know it is there is because a 15-year-old Caulfield schoolboy found it.

Discovered using his home computer and an interstate telescope, Will Stamp's find has been included in the database at the American Association of Variable Star Observers, which reviewed and approved his star on December 29.

The star Will Stamp discovered is half the size of the sun and 300 times the size of Earth. Credit:Joe Armao

A year 11 student at John Monash Science School, Will said the variable star was half the size of the sun and about 300 times the size of Earth. But despite its size, it wasn't easy to spot.

He began observing a patch of sky last April which was close to the south celestial pole, dead south about 30 degrees above the horizon.