The object, believed to be the Russian Kosmos 2430 satellite, put on a pyrotechnic display for northern parts of New Zealand as it burned up while re-entering the atmosphere.
Avid stargazer Dr Ian Griffin, who is also the director of Otago Museum, said all the evidence pointed to the object being a satellite and not a meteor.
Websites dedicated to tracking such objects had been predicting the re-entry of the Kosmos satellite and observations of the event supported that conclusion, he said.
As well as being in "the right place at the right time", its relatively low-speed descent and fiery fragmentation was "what you would expect from a satellite decay, rather than a meteor", he said.
Meteors tended to "flash" across the sky in a few seconds, whereas satellites — being lower in the atmosphere and moving more slowly — could put on "amazing" displays for 20 seconds or more.
"So you do tend to get these beautifully slow decays. They look like slowly breaking up fireballs in the sky."
The suspected culprit was part of a network of early-warning satellites launched by Russia to detect missiles, was about the size of a car and weighed about two tonnes.
It was reported to have drifted off station after failing to respond to controls in 2012.
Dr Griffin said it could be difficult to pinpoint exactly when or where such objects would re-enter the atmosphere.
"Because the Earth’s atmosphere is sometimes more expansive and less expansive, you can never absolutely say ‘this satellite is going to burn up over New Zealand’.
"Within an orbit, you’ll know it will be somewhere between New Zealand and, say, Antarctica."
The Russian satellite’s "really odd" orbit also took it as high as 6000km above Earth and as low as 82km, where it was "brushing through the atmosphere", he said.
"It will decay over the years and it will eventually burn up," he said.
The spectacle was viewed across parts of the North Island, and captured by cameramen covering the one-day cricket clash between New Zealand and Sri Lanka in Tauranga.
Dr Griffin said the "pretty spectacular" event was not a safety threat, as "most of the material probably wouldn’t get down to the surface".
But it was something that would become more common, he said.
"There’s so much stuff up there in orbit, and they say ‘what goes up must come down’, eventually.
"From my perspective, anything that gets people out, excited about the night sky, that’s a good thing."
