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I figured that the shortest shadow would give me the true north south line. I put a 600mm piece of 16mm dowel into the ground on the north side of a 600mm x 400 mm concrete paver. I made sure the stick was level north south and east west. In the morning as soon as the tip of the stick's shadow hit the paver I marked the spot with an X, (at least my son did this as it was a little science experiment for him). Each 1/2 hour or so ( interval not critical) we marked the tip of the shadow.
I was curious as to when local noon was and since I had my iPad with me I used Stellarium and set up an alt az grid and looked north at the position of the Sun. I dragged the sky until the Sun crossed zero and noted the time. I marked the shadow at this time and also two more times after local noon.
i then drew a line through all the crosses and measured the distance from the stick to each marked cross and any part of the line they were on and the shortest one was indeed when the Sun was on the meridian as found in Stellarium. I felt that using Stellarium was 'cheating' a bit but since it wasn't for school as my son had already done this experiment it didn't matter and it was a good way of checking the result.
I did the shadow trick a long time ago without Stellarium and marked the north south line but it had washed off over time. This time I also placed another stick on the south side of my paver inline with the shortest shadow line and then also placed a tomato stake near the fence a few metres away. Now all I have to do is stand on the north side of my paver looking south toward the stake and the SCP is up above it.
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