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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Understanding a 1902 Sumner
From: Brad Morris
Date: 2017 Jan 21, 13:48 -0500
From: Brad Morris
Date: 2017 Jan 21, 13:48 -0500
Hello John
You wrote
- The concept of a datum is meaningless when comparing observed positions.
I think your third point is not valid. When looking at your GPS to fix a place it is not the same datum.
I was thinking precisely the same thing. The GPS solution IS based upon a datum that is not the same as the spherical earth model used in CN. Clearly different and would result in a fix difference.
If, on the otherhand, we mean the CN observation in 1902 compared to a CN observation in 2017, then the point made would be valid.
Brad
