Very nice email in with a helpful photo:
I was stargazing this past week in the Davis Mountains in Texas. I had been pointing out the North Star to my wife using both the Big Dipper and Cassiopeia as you had illustrated.
The next morning I spotted this tree trunk and I realized it was pointing north also in the same direction I had seen the night before.
I placed colored marks and took a picture. The red arrow is pointing north and the blue arrow points south. I understand this asymmetry in the difference of thickness of the rings occurs because of the sun due south at midday.
It was fun to notice and make the connection, thanks for helping me to “read” Nature, it has really made a great difference in my life!
Thanks Dan for your email and great pic.
PS. This is a fun and useful technique, but take care if using it on hills.
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