It may not rival "Manhattanhenge", but the Australian city of Melbourne has enjoyed its own spectacular solar phenomenon.
At 20:27 local time on Tuesday, the setting sun perfectly aligned with the city's east-west streets to cast a golden light between skyscrapers.
"It's similar in concept to Stonehenge," said the Swinburne University astronomer, referring to England's monument where the sun lines up with vertical stones on each of the solstices.
"The example in Melbourne is on a slightly bigger scale, and it has more to do with efficient town planning, rather than anything spiritual."
Melbourne's grid system, designed by surveyor Robert Hoddle in 1837, affords several potential viewing points in the city centre.
But Dr Duffy said trees, trams and low-lying buildings make the choice difficult - not to mention the weather.
Local man David Brewster said he had an excellent view from central William St.
"The Melbourne grid is perfect for this sort of thing," he told the BBC. "It was just a very clear night. You get a nice good view with the tram tracks."
Manhattanhenge has become an attraction for photographers hoping to capture the perfect sunset.
Dr Duffy admitted Melbourne could not match New York for its corridors of towering skyscrapers. But he hoped his campaign, asking photographers to post their favourite locations, would make it easier to enjoy Melbhenge in the future.
"I've been astounding by the response," he told the BBC.
Similar "henge" phenomena also occur in other cities with large numbers of skyscrapers and long straight streets - such as Chicago, Montreal and Toronto.
The term Manhattanhenge was coined by astrophysicist Neil deGrasse Tyson in 1996.
Melbourne will next enjoy the display on 3 November, Dr Duffy said.