A mesmerising spot on the sun

WHEN I drew the curtains in my Portobello home last Saturday morning, I knew it was going to be one of those special Dunedin days. The first shafts of light from the ascending sun were illuminating Mount Cargill, and above the hills which embrace Otago Harbour, the sky was entirely clear. On such days, when others reach for their hedgecutters or their lawn mowers, astronomers like me rush to set up our telescopes to study the nearest star, the sun.

I was hurrying to set up my telescope because astronomers have found, on average, that the best time to observe the sun is during the morning hours when the atmosphere is relatively stable before the heat from the sun stirs it up and makes it more turbulent. By observing soon after sunrise, it is possible to get sharper views of the sun.

By the time the sun cleared the trees in my back garden, my telescope was set up, and by 9.30am I was getting some charming images of an enormous sunspot very close to the centre of the solar disk. Closeup pictures revealed beautiful structures inside the sunspot and I have to confess to being mesmerised by its incredible beauty. The sunspot (astronomers call it Active Region 2738) is enormous; it is nearly twice as big as the Earth.

Sunspots are dark areas in the sun’s atmosphere; they look dark because the gas inside the sunspot is cooler than that in the surrounding area. Sunspots are basically bubbles of cool gas trapped by intense magnetic forces in the sun’s atmosphere. They tend to last for a few weeks before breaking up and fading away.

I must point out that you should never look at the sun using a conventional telescope or binoculars; it is so bright, and puts out so much energy that doing so risks severe damage to your eyesight. Luckily, it is possible to purchase special solar filters which can be attached to telescopes and allow safe viewing. This is great news because, without doubt, the sun is an absolutely fascinating object which certainly repays close attention.