Hemispherical sundial with two noncentral gnomon points

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Hemispherical sundial
with two noncentral gnomon points


Two uneven horizontal gnomons are placed one opposite the other on a concave hemisphere, indicating the hours on two separate nets of engraved hour lines, with the curve of the winter solstice on the one net coinciding with the curve of the summer solstice on the other. The large gnomon had a north orientation (it was especially appropriate for the indication of the summer hours with precision).