Over sea and sky

This month’s full moon occurs at 11.55am on Tuesday. Photographers who want a great shot of our closest celestial neighbour rising in a darkening sky should find a spot with an unobstructed view towards the eastern horizon, writes Ian Griffin.

In Dunedin, moonrise occurs at 6.36pm on Tuesday night. I am sure that the moon will be a magnificent sight as it clears the horizon roughly 3 degrees south of due east. I particularly enjoy watching the moon rise over the ocean. When it is very low in the sky, atmospheric refraction distorts the moon’s shape and colour. Oceanic moonrises are certainly worthy of attention!

While the rising moon is always beautiful, most astronomers don’t like observing at full moon because bright moonlight washes our view of the sky.

That is a little bit of a shame because, as we approach the equinox on September 23, we are entering what is traditionally the prime time for viewing the southern lights and bright moonlight will make any display harder to see.

Auroras tend to be more common near the spring and autumn equinoxes because the sun and earth’s magnetic fields are lined up for a few weeks at this time of year. There is also another reason to raise our hopes for a chance of auroral activity. The sun is becoming more active, with more and more sunspots visible on its surface.

All it will take is for one of these sunspots to explode and hurl material towards earth in what astronomers call a coronal mass ejection. If that happens, provided the sky is clear, stargazers in our region will have a front-row seat for some auroral action!

Since moving to New Zealand in 2013 I’ve seen several beautiful auroras around the time of the full moon. This week’s accompanying photograph was taken during a remarkable display I witnessed from Hoopers Inlet in September 2015.