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I Designing a reflection sundial for the southern hemisphere

  1. Mar 12, 2016 #1

    My aim is to build a small reflecting sundial as designed by Sir Isaac Newton.

    I found from a website that it consists of a ceiling and a small mirror. What I want to know is how it works, the concepts behind it and how to build one. It's for an undergraduate project that I've got.

    What I've learned is that it depends on the latitude, longitude and orientation of the building.
    Resource : http://interiorsundials.tripod.com

    Can anybody help me ?
  2. jcsd
  3. Mar 12, 2016 #2


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    One advantage of such a dial is that it casts a spot instead of a line. This means you could mark the ceiling so as to tell you not only the hour but the time of year.
    The easiest way would be just to set up the mirror and mark the ceiling where the light falls. Of course, you don't want to do that once an hour every hour for 365 days. Anyway, the sun would not always be shining. But you could collect enough samples that you could then fill in the gaps by interpolation.
    There's a bit mor information here https://en.m.wikipedia.org/wiki/Sundial#Reflection_sundials
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