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    Re: Agnostic gnomon and horary error
    From: Chuck Varney
    Date: 2024 Jun 5, 11:43 -0700

    Frank Reed,

    Thank you for posting the photos you took at Mystic Seaport last weekend.

    The two armillary sphere photos confirm what seemed evident from the “Sundial” cover photo; namely, that Edwin Pugsley got his signals crossed when positioning the support post in the 90-degree arc between the gnomon lower end and the equator / time scale ring. This resulted in having the gnomon elevation at, or near, the colatitude angle rather than the latitude angle.

    Using an IrfanView graphic viewer, I got 49.2 degrees as the average of five measurements of the gnomon angle in your first sphere photo. This compares to the 49.3 degree average that I measured on the “Sundials” cover crop that I posted earlier.

    Chuck V.

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