Quote:
Originally Posted by Startrek
Peter,
The solar noon shadow stick method is bullet proof , the human race has been using the suns shadow for thousands of years for time measurement, constructing monuments and buildings , cultural and spiritual reasons and even Indiana Jones used it in Raiders of the lost Ark ( pardon the joke )
The Compass has its use but not ideal for aligning tripods to true south
Glad it has worked out for you
The more accurate you are with your shadow stick set up and true south line , the more accurate and closer you will be to true south and resultant polar alignment
Cheers
Martin
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Thousands of years ago there were no apps to help you find solar noon, (as your method attached to the other thread suggests). You need to determine solar noon another way first and you can do this simultaneously as solar noon will be when the sun is at its highest point and therefore any vertical stick shadow will be the shortest length. The shadow length will vary depending on where you are located in latitude and the current season.
Place the stick as described over a concrete slab and mark the end of the shadow with a dot from morning to evening every hour to every few minutes as you approach solar noon and afterward. When you connect to dots you will get a curved line. Solar noon occurred when the radial (shadow length) is at its shortest. You can confirm this by placing a dot at precise solar noon that you obtained the time using your app but note this was not an option thousands of years ago.
As for the various shadow methods used in the movies all I can say is you must be very lucky to be at the right place at the right time of day and the right time of year and for it to be sunny and not overcast. The best flawed example I remember is in National Treasure when the sun cast a shadow on at a particular spot to reveal a clue. What a fluke to be there at the precise moment the clue was hidden even when they thought they were smart enough to take daylight savings into account. (Still enjoyable movie though!).