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    Re: DIY "Bris mini-sextant": what angles to aim for (and other suggestions)?
    From: Tony Oz
    Date: 2016 Sep 21, 07:18 -0700

    Marty, thanks for your feedback.

    It is easy to reverse calculations. The set of the reflexions' angles (13°, 22°, 26°, 35°, 44°, 48°, 57° and 70° if from the example in the article) comes from the values of the angles between the surfaces. That particular item has 11° between the filter and first mirror, and 17.5° between the filter and second mirror - thus 6.5° between the mirrors. Now, combining the multiples of 6.5°, 11° and 17.5° one cet get all the angle values above (see Table I in the article).

    Strategically choosing the angles between the filter and mirrors one can get a set of reflection angles (i.e. a set of Ho's) most useful/convenient for taking sights.

    Because I'm a complete novice here - I ask what are the most usable Ho's in real live situations? Should I group reflexions around some particular angle? Like to be able to get more sights in the morning and evening leaving wider gap for higher sun altitudes. Or should I make a "bris" more suitable for sun's meridian passage observations?

    Tony

       
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