IT pocket sundial chart |

IT Sundial Chart |

Numerical Data from NOAA

Solar noon, XII on the Ingleside Terraces Sundial, occurs when the shadow of the gnomon lies between the two metal rods at XII. Solar noon is halfway between sunrise and sunset. To calculate clock time for solar noon at the summer solstice, for example, on June 21, look at the above chart. 1 hour 12 minutes needs to be added to sundial time to obtain local clock time PDT on June 22; solar noon on June 22 will occur at 1:12 P.M. PDT.
To determine the time for solar noon on June 21, you can do a calculation: two minute time interval in 9 days from June 13 to June 22 = 120 seconds in 9 days = 13 seconds per day, so solar noon will occur 13 seconds earlier on June 21, which is beyond the accuracy of a sundial. An approximation is close enough; solar noon will occur at 1:12 P.M. PDT on the summer solstice, June 21. |

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