Organiser Brad Tucker said more than 1,800 people were officially counted as having taken part in the event at the Australian National University campus in Canberra yesterday evening, after initially forecast poor weather held off.
"It was cloudy... And right around the time we needed to set the record, the clouds parted and we could see the moon," Tucker, from the Research School of Astronomy and Astrophysics, told AFP.
All those who took part were using telescopes, binoculars or some other device with a high-power lens to study the night sky for 10 minutes at the same time.
The ANU said representatives from Guinness World Records declared the new record of 1,869, which was well above the previous record of 640 people at a single site.
Tucker said the ANU event was one of about 50 taking place around Australia on Friday which would hopefully also break the record for the most people gazing at the stars from multiple sites at one time.