Re: Transit of the sun. RE: SAFE SOLAR VIEWING

From: Jonathan T Wojack (
Date: Mon Apr 22 2002 - 16:11:28 EDT

  • Next message: Alan Pickup: "Decay watch: 2002 April 22"

    > > There are two other similar safe sun viewing methods that are not 
    > > applicable for satellite viewing: 1) pinhole camera; 2) eyepiece 
    > projection 
    > > onto a white screen.
    > Why are these methods not applicable? 
    For the record, I have used the projection system many times.  The only
    precaution you have to make there is that when you focus the eyepiece,
    that you are looking from the side, and no where near the axis of the
    I also support putting a short warning on the SeeSat web pages concerning
    safe solar viewing.  That might seem to be off-topic to some, but it
    could save someone's eyes.  I'd rather have an extra few lines on the web
    pages, then allow someone to go blind from improper solar exposure. 
    Rembember, you only get one pair of eyes.  After that, the only option is
    to become a cyborg.
    Also, keep in mind that there is some amplification of light going on. 
    All of the light from the sun is being directed into a focus. 
    Magnification does decrease the intensity of the light, true, but it
    isn't enough.  You can demonstrate this to yourself by pointing your
    telescope at the sun, focusing the eyepiece through the projection method
    (don't look into the eyepiece !!!), and take a piece of paper and hold it
    in front of the eyepiece.  Within a few seconds, it should start to
    smoke, and soon a part of it will turn black and be eventually vaporized.
     Don't let that happen to your eyes.
    Jonathan T. Wojack       
    39.706d N   75.683d W            4 hours behind UT (-4)
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    This archive was generated by hypermail 2b29 : Mon Apr 22 2002 - 16:18:17 EDT