"As I walked around the grounds, seeing all the people, I thought this must be what heaven's like," said CSIRO Parkes Radio Observatory Operations Scientist John Sarkissian OAM.
Mr Sarkissian - who's been working at the Parkes Radio Telescope for almost 23 years - joined 109 of his CSIRO colleagues on the weekend to help host the 50th anniversary of the Apollo 11 moon landing celebrations.
It was a celebration two-years in the making, where CSIRO initially estimated about 6000 people would make their way out to the observatory.
But the numbers the team ended up settling on was so much higher.
"We estimated 19,500 people, or visitations rather as the numbers overlapped with the tours and visitor centre numbers - it's a rough figure," Mr Sarkissian said.
"We were very fortunate with the weather, people were literally picnicing around the grounds.
"It was a general great feeling all around. It just all came together.
"We started planning in October 2017... Most of the things we had planned, we did.
"And I spent two years worrying about the weather so that was wasted!"
Mr Sarkissian said it was fantastic to have American ambassador to Australia Arthur B. Culvahouse Jr, guest speaker astronaut Dr Andrew Thomas, former NASA scientist Dr Everett Gibson and actor Roy Billing, who all added to the significance and attraction of the open days.
Apollo 11 wasn't just the topic of the anniversary, people were also talking about the plans for the future, including another trip to the moon, and Mr Sarkissian was thrilled to see so many children there.
"Hopefully we had some budding astronomers, engineers and mathematicians there," he said.
"The moon landing still inspires people and why wouldn't it, it was a great human achievement for the ages.
"I was six at the time and I remember what the feeling was like watching it. There were people on the weekend who weren't born when it happened, saying 'I wish I was alive at the time'.
"But this weekend, it gave a glimpse of what it must have been like."
Mr Sarkissian hopes the anniversary and the promotions around Apollo 11 have inspired another generation.
"Most importantly [we hope] that people enjoyed themselves," he said.
"We wanted people to come celebrate with us and help recognise what Australia did in that time, it was a national effort."