Thursday, December 22, 2005

My Sundial and the Winter Solstice (05)

My Sundial.

Constructed during the summer of 04. It uses odd's and ends of left over wood. Indicator arm is 2 8 foot 1x4's separted by about 3/4 inch. The hour indicators are Indiana field rocks. It has been in my mind for many many years to build a large sundial. It has been a lot of fun. And is neat to explain it too people and go down and check it out often.

Here are the results of my winter solstice rock which I added last summer.
The cross bar shadow from the indicator arm should be on top of the rock, at local apparent noon at winter solstice. It looks like I had the rock sitting out about 2 inches (out of about 3 feet) too far. Oh well maybe next year, spring, I will go back over my calculations/measurements. A friend has suggested that it may be caused by my not taking astmospheric refraction into account. I will take a look at this also.

The picture was taken at high noon, local apparent time. Adding 46 minutes for longitude adjustment and subtracting about 2 minutes for the equation of time, resulted in the time being right on, 12:44 PM est.

Now, as the days get longer, the shadow will move back toward the equinox rock reaching it on March 21. Which is where it left last Sept 21. Will the snow be gone then. Time will tell.

As an additional comment. This sundial is not subject to the whims and whines of 'Indiana Time'. Just add the right correction.

If you would like more information about My Sundial email me at tomfortytwonatkconlinecom. fortytwo in numerals, symbol at, dot before com


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