The Whanganui Astronomical Society says light pollution around the Ward Observatory is increasing and want a new darker space for some of the city's telescopes.
Society president Ross Skilton told Whanganui District Council's property and community services committee that the observatory, sitting directly behind the council buildings near Cooks Gardens, is around 120 years old.
The telescope that sits inside the dome is "the largest unmodified refractor telescope still in use in New Zealand," mainly used for educational purposes.
Skilton believed the amount of light pollution around Whanganui from central-city buildings, Cooks Gardens, and the racecourse made star-gazing at the Ward Observatory "quite difficult".
Skilton prepared a slideshow for council, pointing out light pollution during events at Cooks Gardens, as well as race meets at the dog track.
"The other problem we have is lights from buildings including the Grand. We've just been invaded by lights from the city gym too," he said.
"We also have some concern about the velodrome roof if that goes ahead. Every picture we've seen of that it looks like a big white ball."
Skilton said the Ward Observatory and its historic telescope should remain on the same site, a new smaller educational facility could be built on vacant land at Victoria Park, where skies are around 80 times darker.
"Victoria Park has the advantage that it is not lit, and it's used for cricket and not likely to be lit in future," he said.
"There's a nice clear sky and nice big horizon towards the north. This is the sort of place we'd be interested in, not moving the observatory to, but just setting up an education spot."
The society had three telescopes that could be utilised at the site, with another one close to delivery, he said.
Asked by councillor Hadleigh Reid why the society did not propose to move the entire observatory as originally conceived, Skilton said he was worried that moving the entire structure would affect its heritage value.
"We feel that it would compromise its heritage value, and it seems an incredibly expensive thing to do."
Around the council table, there were conflicting views about how the council should respond to the proposal.
Reid questioned why an observatory of such significance wasn't marketed as a tourist attraction, and if the proposed move would provide any benefit to the city from a tourism perspective.
Skilton said with the observatory run by volunteers as well it's status as a district-owned facility, the society had been hesitant to charge more than a gold coin donation.
"The city owns the telescope, so we feel we can't charge a large amount," he said.
Councillor Phillipa Baker-Hogan went on to suggest the council looked at "some sort of report" into the issue of the proposed new spot for the society's telescopes.
Reid agreed, saying he felt the observatory was under-utilised and wanted to see a report into its use.
"I'd love a bigger picture report or plan if really we want to utilise this, especially to have it as a tourist attraction."
Committee chairwoman Helen Craig pushed back on the suggestion, saying that she had not received notice of a motion and that staff were not expecting to complete a report.
"I don't think staff are expecting anybody to suggest a further report comes. This is not an item they've brought, this is an item they've brought in response to requests from councillors after years of discussion."
The council agreed to receive the report, and no further decisions were made.