Is it safe to use a film negative for looking at solar eclipse, or is there any other,safe,way for that ?

Question

I've been trying to find special glasses but no luck :( So I have to find a better way to look at the sun tomorrow, please tell me what can I make on my own and use it for observing, I really don't want to go blind, but solar eclipse is a really nice thing to see, especially when you like science and astronomy. I have a film roll for cameras... can I use that ?

Answer 1

No, it is not safe to use film negative to observe the Sun.

One safe alternative to special solar goggles is to use a filter for arc welding (#14).  These filters provide the level of protection against UV and infrared radiation that is safe for direct solar observation.  You can find them in your local hardware store that carries welding supplies.

Make sure that the filter is intended for arc (electric) welding.  The filters for gas welding do not provide enough protection.

Answer 2

No, you cannot use unexposed film.  It's not nearly thick enough.

Welder's glass #14 would do, if you can find it.  Failing that, you can do eyepiece projection, if you have a cheap refractor (lens-based telescope: DON'T use a mirror-based telescope unless you know what you're doing) and eyepiece you can spare.  Cover any finder on the telescope--you won't be able to use it anyway--and place a sheet of paper a foot or so back from where you would ordinarily observe (straight back from the eyepiece, whichever way that's pointing).  Using the shadow of the telescope as a guide, carefully point the telescope at the Sun, being sure not to look at the Sun, or to put anything between the eyepiece and the paper, least of all your eye.

Once you have the image of the Sun on the paper, focus it until it's as sharp as possible.  It's best to mount the paper securely, so that it does not blow away.  You certainly don't want to have to be holding it throughout the eclipse.

You could also try this with binoculars, by angling a piece of paper on the ground.  Cover one of the binocular objectives.  As always, you must be sure not to allow anything to get in the way between the optical instrument and the paper screen.  Whatever you use, look to create an image that's maybe twice the size of the objective.  (For instance, with 7x35 binoculars, create an image of the Sun that's 3 inches across; with a 60 mm telescope, create one that's 5 inches across; and so forth.)

Unfortunately, the Sun is not very spotty right now, so the sort of stuff that would create interest on the solar disc is mostly absent.  But you still get to see the Moon's advance on the disc.

Answer 3

You can get a #14 shade welders glass....that will insure that you will have a safe view without causing damage to your eyes.

Don't even think of using that film negative.....no way!!...no how!!...