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Astronomy: How to Observe Sunspots

10-14-11 sunpot1305_eruption_Chumack
A sunspot erupts near the sun’s limb. Credit: John Chumack

"There's a little black spot on the sun today…."

Sting and the Police were probably not referring to sunspots, but that song lyric is a rather accurate way to describe them. When sunspots grow large enough, as they have occasionally done within the past couple months, all you need is proper eye protection to see them -- no telescope necessary!

With solar activity on the increase as we head toward the maximum in the solar cycle, larger sunspots are becoming more common, meaning an increased chance for disturbed solar weather and aurorae on Earth. Sunspots tend to cluster in groups and can last for weeks on end before dissipating. Sunspots are dark areas on the surface of the sun that are cooler (about 5000 K) than the surrounding photosphere (about 6000 K). These regions can be several thousand million kilometers square. The darkest inner area is called the umbra and the outer edge is the penumbra. Photographs of sunspots often remind me of the appearance of unhealthy moles, a bit ironic considering the sun's role in skin cancer.

The only way to see these dark spots and protect your eyes is to have the right equipment. Welder's goggles rated 14 or higher are the standard choice for amateur astronomers. While I don't have that, I did keep an old pair of eclipse glasses that came in my Astronomy magazine during a month there was an eclipse, which is what I use to observe sunspots. If you have a telescope, don't try to use goggles or the eclipse glasses to look through it with the telescope pointed at the sun. The intense rays of the sun focused through the eyepieces can cause the optics to crack and shatter.

When you look through the welder's goggles or eclipse glasses at anything around your house, it should look completely black. Then when you turn them toward the sun, you should be able to see just that yellowish-orange orb out of the darkness. Look closely for any small dark mottling on the surface that would indicate a sunspot. To see what the sun's appearance is each day, check the website spaceweather.com for an image of the sun's current condition.

-- Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She writes the SkyGuide for AstronomyToday.com. You can follow her on Twitter at twitter.com/Astronomommy.

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