New Zealanders will get the rare opportunity to observe a total lunar eclipse in their skies on Tuesday 21st December.

The eclipse will begin before moonrise in New Zealand, 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 21st 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 says, “The eclipsed Moon is likely to appear copper coloured to us. 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 26th 2010. This will be the first total lunar eclipse in nearly 3 years, the last being on February 20th 2008. The next lunar eclipse seen from New Zealand is a total eclipse on June 15th 2011.

The eclipse of the Moon will be visible to the naked eye, but Auckland’s Stardome Observatory will have telescopes set up (weather permitting) after special shows in the planetarium about eclipses that night. They expect a large crowd of amateur stargazers and astronomy enthusiasts to gather and view the event.

The special eclipse shows in the Stardome planetarium on Tuesday 21st December will cost just $10, and screen at 7pm, 7:30pm, 8pm, 9pm and 9:30pm. For bookings and information phone 09 624 1246 or visit stardome.org.nz

Image: A previous eclipse which Stardom expects will look similar to the upcoming one / Stardome