The National Space Centre said it did not consider the Sturgeon Moon to be close enough to the Earth to be called a “supermoon”.
Although there is no official definition, it said supermoons must be closer than 360,000km, but last night’s, which peaked at 02:36 BST, was 361,408km away.
Much closer than the average Earth-Moon distance, but not quite close enough.
However, Dhara Patel, an expert at the National Space Centre, said not everyone would agree.
She said: “Different groups have come up with different rules surrounding what constitutes a supermoon.
“In one broad sense, the Moon is considered to be a supermoon if the Moon is within 90% of its closest distance at the exact moment of full Moon.
“In another sense, some use the definition that when the Moon is within 360,000km of the Earth at the time of full Moon or new Moon.
“In the strictest sense, a supermoon is the single closest new Moon and full Moon of the year, so by that definition there can only be two a year.”
The National Space Centre compared the debate to another about whether private trips to space, like ones taken by billionaires Jeff Bezos and Richard Branson, make them astronauts or space tourists.
The full Moon in August was named the Sturgeon Moon by Native American fishing tribes, due to there being an abundance of the fish at that time of year.
The Royal Museums Greenwich said it had also been called the green corn Moon, the grain Moon, and the red Moon, due to the reddish appearance it often has.
Full Moons occur every 29.5 days when the Moon is directly opposite to the Sun.