A photo taken in February 1965 has sparked debate over a UFO seemingly seen in the background.
The official Defence Force photographer snapped the picture of the navy cruiser Royalist whilst the ship was on its way back from Waitangi celebrations.
The photograph was recently dug out for a new website for Devonport Navy Museum. The staff member who found it checked the negative, then called in a digital imaging expert, who established that the image was in the original.
Opinions on the identity of the 'UFO' differ.
Museum director David Wright said there was nothing to explain what it was.
The object appeared to be some distance in front of the ship and none of the sailors working on the bow was taking any notice, as would be expected if something was going on.
He said it looked to be too distant to be a dinner plate thrown from the bridge and the same would apply to a clay pigeon used as a shooting target. The angle of the object and absence of visible lines suggested it was not a parachute.
However, Carter Observatory senior astronomer Brian Carter disagrees.
He said that when the object was enlarged it had a sharp edge to it. Under the same enlargement, the edge of the cliff on the right and the bow of the ship were not that sharp, he said.
That suggested the object was quite close and therefore quite small.
He believed it was something thrown from the bridge or some other part of the ship.