WARNING: Never look directly at the sun! Permanent damage to your eyesight may result if you do not follow the correct guidelines for solar astronomy. Always seek professional advice before observing the sun.
Have you seen the sun lately? No, no, don’t look right at it with your eyes. Ouch. I’m not asking about the weather, either, or at least Earth’s weather. The sun itself is a sight to behold right now, and it is creating some fascinating space weather as well.
Sunspot 1302 made its way around the limb of the sun with a bang last weekend, sending off some serious solar flares that were caught by one of my personal favorite spacecraft, the Solar Dynamics Observatory, or SDO.
The active region continued to erupt as it rotated towards Earth, creating beautiful aurora for those lucky viewers at high latitudes of the Northern Hemisphere as charged, energetic particles slammed into the Earth’s atmosphere.
Our home star is a very quiet beast, at least compared to the vast majority of stars in our Galaxy. So what causes its temper tantrums?
As the sun rotates, it is not a solid sphere, but instead a vast, roiling ball of superheated plasma. Magnetic fields get twisted about, and active regions crop up on the surface causing a bit of chaos.
However, the sun looks so peaceful to us down here, and active regions actually show up as dark spots when viewed in visible light. These “colder” dark spots are “only” about 4000 Kelvin compared to the 5780 Kelvin of the sun’s photosphere. Also, they are bigger than Earth. Not so peaceful anymore, eh?
A student looks through a telescope fitted with a solar filter (notice it only uses part of the aperture) while Dark Skies, Bright Kids volunteer Paul looks on. Thanks to Gail for digging this up for me!
You can see sunspots yourself with good protection or some clever use of equipment. One of the best ways to view the sun is through a telescope WITH a high quality solar filter on the light-collecting end. Through this, the sun looks like a disk, and you can see features like sunspots and solar prominences. If you don’t have a solar filter, you can still (CAREFULLY) point a telescope or binoculars at the sun and project the image onto a piece of paper.
You can even find directions on how to make your own sunspot viewer if you have an extra lens lying around, or buy a ready-made one. We have at least two of the latter in our astronomy department, and I had the dubious job of being in charge of the optional sunspot lab at the heart of the last solar minimum. If you are really dedicated, you can track a sunspot’s progress over several days and make a measurement of the rotation rate of the sun’s surface, at least for a particular solar latitude.
Lucky for you, as I was writing this, the clouds cleared away and I literally ran outside to set up my telescope and demonstrate the projection technique.
For the curious, it is a Meade ETX-90.
This was the best I could do while holding up a white cardboard box in one hand and my cell phone camera in the other. In reality, the projection is much more detailed, but even here you can see that it’s clearly our buddy 1302! Remember, DO NOT LOOK AT THE SUN THROUGH A TELESCOPE OR OTHER LENS. You have to use shadows to safely point the telescope right at the sun and NOT walk behind it at the right height such that the projection beams you in the eye. (Ow.)
Though there is something to be said for seeing the sun in real time with your own PROTECTED eyes, you can also log on to SDO’s website to see today’s pictures of the sun, many of which are in the ultraviolet and x-ray wavelengths. Now that active region comes to life!
I am glad to see that my go-to website for many years before SDO was launched is still going, the daily sun images from the Solar and Heliospheric Observatory. Even if you, like me, are too far away from the North Pole to get any gorgeous aurora view, you can still see the sun and new active region in all its glory in real time with a little bit of refraction and patience.
Image Credits, from top: NASA/SDO; Dark Skies Bright Kids; me; also me; NASA/SDO.