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    Re: Bris Sextant Solar Filter
    From: John Almberg
    Date: 2016 Jun 15, 20:54 -0400
    That’s great for taking a photo, but would you want to stare at one of those sun images for several minutes, waiting for it to touch the horizon? How about several times a day on an extended voyage? I sure wouldn’t.

    NOTE TO FUTURE READERS: It’s fine to use a microscope slide or whatever if you only intend to play with your Bris once or twice — if you are careful. But if you intend to actually build and *use* a Bris-style mini-sextant, do some research beyond reading this thread, and build sufficient solar filtering into your sextant to make it sun-safe. Just my opinion, but seriously, you should listen to me. 

    — John


    On Jun 15, 2016, at 8:23 PM, Greg Rudzinski <NoReply_Rudzinski@fer3.com> wrote:

    John,

    See image of my homemade microscope bris showing images 5,6,7,8 through a 52mm polarizer and UV camera filter. Shows dimmer than sun reflections off the water. Hasn't been a problem for me. Just dont look directly at the Sun through it.

    Greg Rudzinski

    From: John Almberg
    Date: 2016 Jun 15, 18:31 -0400

    The series of reflections produced by a Bris sextant reduce the intensity of the Sun, but not nearly enough to be safe for the eye. A sun-safe solar viewing filter must *always* be used when viewing the sun through a Bris mini-sextant directly. Alternatively, you can use a pinhole to project an image of the sun through  the mini-sextant onto a viewing screen.
    — John


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