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    Re: Simplified Bris Sextant
    From: Greg Rudzinski
    Date: 2012 May 9, 08:41 -0700

    Here are images of the latest Bris Sextant derivative. This one uses a round glass instead of a microscope slide to act as a whole horizon mirror and some mirror stock is used to replace the other microscope slide to act as an index mirror. This makes daytime Moon and twilight Venus observations possible. Preliminary calibration is done using an already calibrated 50 mm lens on a DSLR . This way I can pre-calculate the time I need to be at the beach for an actual natural horizon trial.

    Greg Rudzinski

    [NavList] Simplified Bris Sextant
    From: Greg Rudzinski
    Date: 7 May 2012 19:37
    Making a simplified Bris Sextant only requires gluing two microscope slides together with a gap at one end. The larger the gap the greater the angular deflection of the reflected Sun. I used a 0.7 mm pencil lead to set a gap and got 1* 57.8' of deflection. Inspect the linked image and you will see that the reflected image is the sum of four images one on top of the other. This must be from the front and back surface reflections from each slide. The best a navigator can probably hope for is 1' to 2' of precision on a home made version. Still this is pretty good for something that can get lost in a shirt pocket.

    Greg Rudzinski
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