Lunar eclipse may be on show before sunset tonight

Wanganui residents will get the chance to see a full eclipse of the moon this evening.
But for the best view of the eclipse they'll need a high vantage point - and clear skies.
Stardome astronomer Grant Christie said tonight's eclipse is an uncommon type called a selenehelion, where the eclipse happens as the sun is setting and the moon is rising.
The sun will set at 8.48pm and the moon will rise at 8.44pm.
The moon will enter total eclipse at 8.41pm - so it will rise already in eclipse.
"This will mean that Wanganui won't get the best view of the eclipse as the north-eastern horizon, where the moon will rise, is slightly obscured by hills," Mr Christie said.
"The higher up you can get, the better view you will have."
The long summer twilight will also make the rising moon less visible than normal.
Mr Christie said a lunar eclipse happens when Earth, the sun and the moon are in a straight line, the moon being within the shadow cast by Earth.
He said the total eclipse will last until just before 10pm.
Wanganui's weather could spoil the party, as heavy rain is forecast for later today.
The last full lunar eclipse visible in Wanganui happened in August 2007. The next one will occur in June 2011.
WHAT IS A LUNAR ECLIPSE?
- A lunar eclipse occurs when the moon passes behind Earth so that Earth blocks the sun's rays from striking the moon.
- This can occur only when the sun, Earth and moon are aligned exactly, or very closely so, with Earth in the middle.
- Lunar eclipses always happen on the night of a full moon.
- Total lunar eclipses are more common than total solar eclipses.
- Unlike a solar eclipse, which can only be viewed from a certain relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth.
- A total lunar eclipse lasts for a few hours, whereas a total solar eclipse lasts for only a few minutes at any given place.
- During a total lunar eclipse the moon changes colour - it can be anything from nearly invisible to blood red, depending on the amount of dust in Earth's atmosphere.
- The range of colours of the moon during eclipses is known as the Danjon scale.