The moon will be obscured by the Earth's shadow later this month in the first total lunar eclipse visible from New Zealand in almost three years.

The eclipse will begin before moonrise on Tuesday, December 21, so in Auckland it will rise in partial eclipse. Further south the moon will rise in total eclipse, while the lower South Island will see only the tail-end of the eclipse.

In a lunar eclipse the moon is obscured as it passes through the Earth's shadow. A total lunar eclipse only occurs when there is a full moon.

On December 21, the sun will set at 8.36pm and the moon will rise at the same time on the opposite horizon. Mid-eclipse is at 9.17pm.
Stardome astronomer Dr Grant Christie said the eclipsed moon is likely to appear copper coloured.

"This is caused by a scattering of sunlight as it passes through the Earth's atmosphere, removing the blue light and passing mainly the red, some of which weakly illuminates the moon.

"You will need a clear eastern horizon to be able to see it though. Over water would be ideal, and the further north you are located the better. In Auckland the eclipsed moon will not be visible until around 9pm. It will be necessary to use a higher vantage point like the top of one of our volcano cones to view this event."

The last lunar eclipse was a partial eclipse on June 26 of this year.

This will be the first total lunar eclipse in nearly three years, the last being on February 20, 2008. The next lunar eclipse seen from New Zealand is a total eclipse on June 15 next year.

The eclipse of the moon will be visible to the naked eye.

- NZ Herald staff