Messing around with sundial

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  • LCHIEN
    Internet Fact Checker
    • Dec 2002
    • 21101
    • Katy, TX, USA.
    • BT3000 vintage 1999

    Messing around with sundial

    Always curious about time keeping, clocks and... SUNDIALS

    Quick research on the internet says the gnomon has to be at an angle same as your latitude... mine is 29.76
    cut a guide alignment block at a hair less than 30. Using a 4" nail as the gnomon.
    My other choice was drilling a hole at almost 30 using the drill press and a angle drilling jig of some sort with a 1/8" or 3/16" dowel as a gnomon.
    Click image for larger version  Name:	20240512_185327.jpg Views:	10 Size:	215.3 KB ID:	858875

    30 minute project later...

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    So the next instruction is to point the gnomon at the north (solar) pole.

    darn. Overcast.
    Needs new batteries, I guess.

    The long term problem is the 5, large 33-year old live oak trees. Not too many continuously sunny spots left on my property.
    Last edited by LCHIEN; 05-13-2024, 12:14 AM.
    Loring in Katy, TX USA
    If your only tool is a hammer, you tend to treat all problems as if they were nails.
    BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions
  • leehljp
    Just me
    • Dec 2002
    • 8470
    • Tunica, MS
    • BT3000/3100

    #2
    "darn. Overcast.
    Needs new batteries, I guess
    "

    They just don't make them like they used to!

    QUESTION: How did you arrive at the placement of the horizontal line that is marked with "6" on both ends, and is where the gnomon is also located?
    Hank Lee

    Experience is what you get when you don't get what you wanted!

    Comment

    • LCHIEN
      Internet Fact Checker
      • Dec 2002
      • 21101
      • Katy, TX, USA.
      • BT3000 vintage 1999

      #3
      Originally posted by leehljp
      "darn. Overcast.
      Needs new batteries, I guess
      "

      They just don't make them like they used to!

      QUESTION: How did you arrive at the placement of the horizontal line that is marked with "6" on both ends, and is where the gnomon is also located?
      The point of the Gnomon is located on that line, I arbitrarily chose that point, close enough to one side of the base to still have 6 oclock radials of a decent length. Any farther down and the 6 o'clock radials would be very short. Higher and you'd just use half the base.

      So yeah, the point of the gnomon is a little off. I drove the nail after I drew the markings...

      You could in fact lay this out on a square or rectangular base, some use a semi-circle; a circle is not a requirement. The time lines radiate outwards from the junction point of the 12-oclock radial and the 6 o'clock radials. One hour every 15.

      Higher latitudes with long summertime daylight hours you can put radials for 5 AM and 7 PM below the horizontal line and see shadows.

      This clock doesn't know about DST, though.

      If you look at this one, the line connecting 6 and 6 (VI to VI) is through the base of the gnomon. and the Line is offset from the center of the circle an arbitrary amount.
      Click image for larger version  Name:	image.png Views:	0 Size:	1.32 MB ID:	858882
      Last edited by LCHIEN; 05-13-2024, 12:34 AM.
      Loring in Katy, TX USA
      If your only tool is a hammer, you tend to treat all problems as if they were nails.
      BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

      Comment

      • LCHIEN
        Internet Fact Checker
        • Dec 2002
        • 21101
        • Katy, TX, USA.
        • BT3000 vintage 1999

        #4
        Click image for larger version  Name:	image.png Views:	0 Size:	322.5 KB ID:	858881

        A few other designs. Pondering what I could do to make an interesting modern looking design.
        Building a quickie always gives you insights.

        A useful link:
        https://www.instructables.com/Horizontal-Sundial/

        And you can get your Lat/Lon by right clicking on your location on Google Maps.
        Click image for larger version

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        Last edited by LCHIEN; 05-13-2024, 12:38 AM.
        Loring in Katy, TX USA
        If your only tool is a hammer, you tend to treat all problems as if they were nails.
        BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

        Comment

        • capncarl
          Veteran Member
          • Jan 2007
          • 3575
          • Leesburg Georgia USA
          • SawStop CTS

          #5
          How about a 3D printed digital sundial? My oldest printed one out several yrs ago for me to play with. Mind blowing! I didn’t set it up in a permanent location, if that’s even possible. Google it.

          Comment


          • LCHIEN
            LCHIEN commented
            Editing a comment
            I saw those... clever idea.
        • LCHIEN
          Internet Fact Checker
          • Dec 2002
          • 21101
          • Katy, TX, USA.
          • BT3000 vintage 1999

          #6
          So I learned one thing already... using a round item like a nail for the gnomon is not a good idea.
          The shadow it casts is wide so making the time determination imprecise.
          The use of a triangle as a gnomon casts a sharp line of light/dark which is much more precise. Its only a wide shadow at noon.
          Loring in Katy, TX USA
          If your only tool is a hammer, you tend to treat all problems as if they were nails.
          BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

          Comment

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