You’ll burn your eye out kid.
New England has been totally lame for evening observing lately, but this is where I live, so this post will be about one very appealing alternative that I’ve touched on before: solar observing. With the Venus transit coming up next year, expect to hear a lot about this in the next few months. Fortunately, the relevant equipment has come along way in the last decade.
First off, I have to say a word (OK, more than one) about safety. Once upon a time, there were a wide range of products available that made it seem as though people of yesteryear did not value their lives, limbs or senses. One of these products was the solar viewing eyepiece, which was just a regular eyepiece with a thin bit of coating or foil added between (or on) the lenses. These worked well, for a while, but had a tendency to crack under the intense energy of focused sunlight, with no warning. Maybe you remember using a magnifying glass to burn your initials (or dirty words) into a piece of wood when you were a kid. Now imagine doing that to your retina.
These days, there are MANY superior options, both in terms of safety and performance, but mostly safely. In all cases (but one, which I’ll point out) to view the sun responsibly, you need to either have a dedicated solar scope, have a solar filter on the outside of your scope or simply use a non-telescope device.
Humans love to focus on the exceptions, so let me get it out of the way. Baader makes a special solar diagonal that, as far as I can tell, is the only eyepiece-end solar mod for a standard telescope that is safe to use. Of course, by using this on many modern scopes, which are often filled with matte black baffles that will gladly heat up immediately, you’ll have a different set of issues to deal with. Also, these can ONLY be used on refractors.
OK, so now that’s out of the way…
For most of us, we non-solar and non-refractor telescope having 99%, the cheapest and best option is to put a good solar film “cap” on the end of our regular scope. I swear I’m not a shill for Baader, but they happen to make a very good and widely used solar film. No matter who makes it though, the ratio of light that penetrates it should be in the range of 100,000 to 1, or 0.00001% of incoming light. That’s not much, but the sun emits quite a bit and you’ll have a bright image with sunspots visible.
But what about all those cool CMEs and prominences? WHAT ABOUT THEM?
Ok, so you want to see the really cool stuff. Fair enough, it’s pretty cool after all. What you’ll need is a scope with a specific type of filter (often integrated, but in some cases available as a mod) and they’re not really cheap. What you want is a Hydrogen-Alpha (Hα or H-alpha, which only allows the transmission of light emitted from hydrogen) filter and, in my opinion, the best way to get one is to have it built into a solar-dedicated scope. Lundt and Coronado are the brands to look to for this and the cheapest ones are around $600, the same price as the Baader wedge. Of course, they quickly get more expensive and you get different things with the pricier models. It’s no challenge to spend $3000 on a middle-range solar scope, but you do get something very special for your money, a view of solar activity that will astound anyone who sees it.
Pictures don’t even do this type of viewing justice, it’s really that spectacular.
Don’t have $600-$6000 to spend? Don’t think you’re simply out of luck, you still have options. Good, cheap options too, like cutting a pinhole in a box and putting it over your head, which does actually work, but won’t give you much detail. Or, if you want to use something in public and not have people think you need to have the police assist you back to the institution from which you must have escaped, there are items which might even draw a small crowd of curious passers-by.
“Be careful whose advice you buy, but be patient with those who supply it. Advice is a form of nostalgia; dispensing it is a way of wishing the past from the disposal–wiping it off, painting over the ugly parts, and recycling it for more than it’s worth. “
Also, don’t forget your sunscreen.