The Australian National University expects to shatter its own stargazing Guinness World Record on Wednesday, and is urging Canberrans with stars in their eyes to turn their eyes to the sky.

The university set the record for the most people stargazing across multiple venues in August 2015, when 7960 people across 37 locations in Australia stared simultaneously at the night sky.

ANU astronomy professor Dr Brad Tucker said more than 3100 people had already pre-registered for the ANU location of Wednesday night's Guinness World Record attempt for the most people stargazing across multiple venues. Credit:Sitthixay Ditthavong

Dr Brad Tucker, from the ANU's research school of astronomy and astrophysics, said he expected that mark would be easily eclipsed on Wednesday.

"Already, we've got 3100 people signed up for the Canberra event alone, and we have more than 250 sites nationally this time," Dr Tucker said.