By IAN GRIFFIN

It seems that the moon will always dominate July. Thirty-one years ago this month, United States astronauts Neil Armstrong and Buzz Aldrin first explored its "magnificent desolation."

For me, the events of July 1969 are interwoven with memories of childhood, and I fondly remember being kept awake late by my parents to watch that first moon walk.

This July, on the exact anniversary of the launch of Apollo 11, I will be keeping my own children up late, so that they too will have a special lunar event to remember.

On the night of Sunday, July 16, New Zealanders will see - weather permitting - the longest eclipse of the moon since 1859.

There will not be another total lunar eclipse visible from New Zealand until August 2007, and it will be the year 3000 before anyone on Earth will again see one as long.

Best of all, no special equipment is needed to see the eclipse. Your own eyes, a few blankets, a comfortable chair and some good company are all that is required.

The eclipse officially begins at 10:47 pm on July 16, when the bright full moon enters the lighter part of the earth's shadow, called the penumbra.

However, it will not be until 11:57 pm that the best part of the eclipse will begin, when the Earth's dark shadow (called the umbra) becomes visible on the lunar surface.

For the next hour this shadow will noticeably change the moon's visual appearance as it slowly creeps across the lunar disc.

By 1:02 am the moon will be totally eclipsed, and for one hour and 47 minutes it will hang, blood red, against the rich starry backdrop of Sagittarius.

At 2:49 am the total part of the eclipse will end, and slowly, over the next two hours, the moon will regain its normal lustre.

An eclipse like this occurs when Earth passes between the sun and the moon. As a result, direct light from the sun is cut off and the moon is lit only by sunlight passing through the Earth's atmosphere.

An astronaut standing on the moon on July 16 would see the sun disappear, and the night side of the Earth would be surrounded by a red ring created by the simultaneous visibility of all the world's sunsets and sunrises.

Eighteen years ago, again in July, there was another long eclipse of the moon. On that occasion the moon became hard to see, and wonderful variations in colour and intensity were visible.

These effects were caused by clouds of dust high in the Earth's atmosphere filtering the sun's light en route to the moon. The dust came from large volcanic eruption that occurred a few months before the eclipse.

There have been no recent large volcanic eruptions, so this month's eclipse is not expected to be quite as remarkable as that of 1982.

One of the best things about astronomy, though, is that anything can happen. For this reason I will be sitting outside the Auckland Observatory on the night of July 16, with my kids, warm clothing, some cocoa and some great expectations.