Monday, November 7, 2011

Big Sunspots

Tomorrow afternoon, I'll be looking at the Sun with my observational astronomy students.

We have a solar filter (it basically looks like the one at right) for our telescope which passes only a small fraction of the visible light and cuts the harmful infrared and ultraviolet radiation.  Without it, looking at the Sun with a telescope will result in instant damage to your eyes.

The reason we're going to take a look at the Sun (other than the fact that it's interesting), is to observe a large group of sunspots that have been rotating into view.  It's called Active Region (AR) 1339.

Below is a solar image from 2345 UTC (7:45 pm EDT) on November 5 showing the large active region around the 10 o'clock position on the face of the Sun.

Check out this image of AR 1339 from Mexican amateur astronomer César Cantú (click here for a higher resolution image on his website).

When looking at this sunspot group, keep in mind that each of those darker dots is about the size of the Earth!  They're incredibly beautiful close up - almost looking like abstract art.

Sunspots often flare up, causing coronal mass ejections (CMEs) that send billions of tons of ionized gas screaming out into space.  If the sunpot is facing toward the Earth, this ionized gas interacts with the Earth's magnetic field and outer atmosphere resulting in a geomagnetic storm and strong auroral activity.

Keep an eye on which will issue alerts if there are any CMEs in the next few days and the possibility of seeing an aurora.

Sunspots are fascinating phenomenon, I think I'll write more about them later this week.

1 comment: