Comet a dawn visitor to Wairarapa

Comet Lovejoy will be visible to Wairarapa viewers this month. PHOTO/FILE

Stargazers will have to rise early to catch a once-in-a-lifetime glimpse of Comet Lovejoy hurtling across Wairarapa skies.

Comet Lovejoy - discovered last August - was racing north across the heavens at up to 30km a second, according to Dr Grant Christie, from the Stardome Observatory in Auckland.

The illuminated mass of ice will come within about 70 million kilometres of Earth and while being named after its Australian discoverer, Terry Lovejoy, was known less romantically as C/2011 W3.

The comet, believed to be about 5km in diameter, would be visible to the unaided but expert eye over the next few days and could be seen most easily with binoculars.

The lone wanderer would be difficult to see by the middle of the month before vanishing beyond the horizon in late January and not returning to our skies for several thousand years.

Wairarapa astronomer Richard Hall says the comet is at its brightest at present as its orbit is completed about the Sun "before heading off into deep space again", and was best seen at dawn from about 4am in the southwest part of the regional sky.

"If you're an astronomer it's visible but certainly easier to see with binoculars. It's not something that is easily visible at the moment to the general public. You've got to get up in the early hours of the morning - a dawn sky - you can just spot it, if you know where to look, with the unaided eye," he said.

"It's just like a fuzzy spot and nothing really spectacular like we've had before. Of course it can brighten."

The full moon on Monday made viewing somewhat more difficult, he said, when "what you ideally need is a nice inky black sky" to contrast the comet as solar winds boil and turn its icy substance to a tail of glowing gas and dust.

There had been some reasonably good images captured of the comet in New Zealand and astronomers throughout the country were in the early morning tracking its progress as "comets can be wildly unpredictable".

"On occasion you can get explosions and it can brighten right up and suddenly become very visible to the naked eye. It can be affected by solar activity as well and if there was a big eruption on the sun, that in turn can dramatically affect the comet. "