In preparation for the 2017 total solar eclipse, I recently purchased a mounted Astrozap Baader film filter for my Sky-Watcher 100 ED, and also a sheet of the Baader film to make hand-held naked eye filters with. When reading the package (for the sheet film), I read the following warning:
AstroSolar™ Safety Film reduces the intensity of incident sunlight by a factor of over 100,000. According to current medical research, the filter (when properly used) provides complete protection against thermal damage to the retina (photocoagulation).
Under certain circumstances, any intense source of light (e.g. spotlight, laser beam, welding arc, the sun) can trigger so-called photo-toxic processes in the eye. In extreme cases, such reactions can have an additive effect over time, leading to deterioration of the vision.
Please note: This filter provides protection against solar radiation similar to that offered by welding glasses. However, as long as it is not absolutely certain that even welders glasses completely hinder phototoxic reactions, the same reservations must apply to this solar filter.
Therefore, exercise your own best judgment when using this product.
Although we have never heard of a single case of eye damage in 10 years of sales of this product to thousands of telescope users, and knowing that welders ply their trade for years, while the solar filter’s use can be measured in minutes, we believe it appropriate to inform you of the current state of scientific knowledge.
In any case, it is advisable to interrupt solar observation occasionally and look at other objects. If you have any doubts at all, especially in cases of known excessive eye sensitivity, consult your ophthalmologist or optician.
My first thought is that this is just another legal disclaimer, just in case someone does something stupid. But then I started wondering if there is any real concern here. I've never heard of even dedicated solar observers using this film having been harmed. Of course, I understand the importance of checking the film for pinholes before each use.
Edited by John O'Hara, 06 April 2017 - 01:03 PM.