|Sun in White Light. A 99.9% filter was used. The dark spots are sun spots.|
If you're ever interested in looking at the sun there are a few things you need to know. First, and I can't stress this enough, it can be DANGEROUS. Blindly so. Once, several years ago, I projected the sun onto a white piece of paper to show a student what sun spots looked like. If you keep the paper far enough away from the eye piece it is quite easy to do. After a couple of seconds I took the paper away and was doing some explaining. I made the mistake of moving my hand in front of the telescope eyepiece (which was still pointed at the sun) and in less than a second I had myself a second degree burn. The point is, unless your are confident in what you are doing, don't. You can literally go blind.
Despite this, its actually quite easy to observe the sun. Go to any hardware store that sells welding equipment and get a piece of Number 12, 13, or 14 welder's glass (which I'll call a solar filter from now on since that's what we're using it as). Don't get anything less! These types of glass are dense enough to block out the dangerous UV light coming from the sun. Others are not. Once you have said piece of glass, hold it up to your eyes and find the sun.
|Sun in HA showing a nice Prominence on the right|
Using Welder's glass will not magnify the sun however. So what you'll see will probably lack any significant detail. I have only once ever seen a sunspot big enough to see just by using a filter. To get a better view, you could attach two solar filters in front of each lens of pair of binoculars. Now you should be able to see some black grains on the surface of the sun. No, your binoculars are not dirty! Those are sun spots.
For even more detail you'll need to step up to a full sized telescope with a proper solar filter (you could of course still use Welder's glass but it would be difficult to find a piece big enough; in addition I would worry about a makeshift filter falling off the telescope). Depending on the size of you're telescope you should be able to see quite a bit of detail! The surface of sun changes for a variety of reason; like the Earth, the sun rotates so we see different faces of the sun at different times. In addition the energy produced deep inside the core of the sun is always seeping to the surface; this creates convection currents, radiation and powerful magnetic fields that shape the surface. If you're fortunate enough to have a telescope 6" in diameter or larger you'll probably notice there are two distinct parts of Sun Spots. The darker central part is called the Umbra while the dimmer outer layer is the Perumbra.
|Sun in HA showing granulation and Spiculas and Filaments|
A completely different type of solar observing involves using a Spectroscope (see my previous post on homemade Spectroscopy) to see the Solar Absorption Spectrum. The spectrum below was taken using my homemade spectroscope and calibrated using RSPEC.
All of these are exciting and interesting ways to look at the closest star to Earth, our sun!