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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: David C
Date: 2017 Jan 21, 14:42 -0800
From: David C
Date: 2017 Jan 21, 14:42 -0800
My concern about datum was when we check our fix using our GPS. My GPS can be set to many different datums. Just now I changed from WS84 to EUR79 and my backyard changed coordinates - not much but they changed.
I was thinking that the GPS and the almanac should be on the same datum and I do not know what the almanac uses.
John my thoughts exactly.
If the 1902 and 2017 NAs are calculated in the same way then observed positions should match (provided the local vertical and the greenwhich meridian have not changed).
