observing the sun with an X-Ray sheet

[abumuhannadh]

hi,

when i was a kid, there were at least three partial solar eclipses in my area. each time i watched it with an X-Ray sheet. (i have used it as late as 2004, to view the Venus transit that time) it was comfortable to look at the sun with it, and there were no solar viewing glasses available.

i have read that it is harmful to view the sun with an X-Ray sheet. what is the credibility of this?

if it is comfortable to the eye, still can it be harmful?

Ali.

[brianb]

I wouldn't reccomend it but it's probably reasonably safe for naked eye viewing (you'd need a couple of layers to dim the sun enough). Silver based film, fogged and developed to a high density, is quite effective at filtering out invisible but harmful radiation (UV and IR) but colour film which is dye based tends to transmit rather a lot of IR even if it's very dense in the visible light band. Do NOT use ANYTHING except proper solar film for viewing the sun through a scope or binoculars!

[Merlin66]

Yes!

There's no nerves in the retina so you don't feel the heat when it cooks!!

X ray sheet or any other exposed film doesn't reduce the UV and IR radiation reaching the eye; damage can occur.

There was an article in Sky and Telescope a few years ago that compared various eclipse "filters" - the only safe one is the Solar Film which has a ND (neutral density) rating of 5 ie only 0.00001% of the visible light gets through across the whole energy spectrum from the UV up to the NIR.

Don't take any chances with the Sun.

[beamish]

There's no nerves in the retina so you don't feel the heat when it cooks!!

Funny how this has never occurred to me - one expects to "know" when harm is being done to oneself- but the idea of just losing your sight in an instant