Solar filter question

[The Warthog]

A lot is made of inspecting your solar filters, understandably, and, just to reassure my gentle readers, I wouldn't use one that appeared to have any damage. I always check my solar viewer before looking at the sun. That being said, if your solar filter has a pinhole or two of, say, .05" diameter, how much danger are you in if you look through it accidentally?

[Greg]

Good one WH..

I had a new Baader one once, when I got home I held it up to one of the low voltage kitchen lights and it was full of little pin holes!

Needless to say I took it back.

So as WH says check all of your filters and as a matter of fact all your solar viewing equipment before use.

[Astroman]

No filter will be "perfect", there will undoubtedly be some very small "holes" in the coating. Careful inspection may reveal these holes to actually be inconsistencies in the thickness of the coating. Very, very slight "bright spots" should not be confused with actual pinholes. Even a new filter may show some differences in brightness across the filter. Something the size of which you describe, WH is probably not of much concern, to tell you the truth. Instead of relying on your eye as a test instrument, try this:If you see a bright spot with your eye, try holding your hand under the spot and let the sunlight shine on it. If it makes a bright spot or spots large enough to see clearly, it's probably a bad thing. If not, you're ok. The good news is, you can mask it with some dark paint or opaque nail polish, especially if it's a glass filter, and notice no degredation of the image. Baader film can be masked with flexible tape, such as electrical tape, on the inside surface. You can check the image through ep projection on a card or something. If you see bright spots on the card, you didn't fix it.

Again, that said, it's best to be ultra careful. If it makes you uncomfortable, replace it. Myself, I tend to be somewhat reckless, much to my chagrin. Always looking for some new edge in observing, I weigh all safety considerations before rushing in where angels fear to tread, as it were.

P.S. I've been observing the Sun for going on 20 years and even with some recklessness, I still see fine. Just ask my optometrist. :shock: