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Re: Is 20" arc error compatible with "free of error for practical use"?
From: David Pike
Date: 2024 Aug 27, 10:44 -0700
From: David Pike
Date: 2024 Aug 27, 10:44 -0700
Earlier I wrote " At 6AM or PM at the Equator a 30” measuring error would move a Sun line ½ nm, barely the thickness of a 2B pencil line on a typical sea chart. At 60 N or S it would be half of that." Before Frank picks it up, I'm beginning to think the last sentence is neat, plausible, and wrong wrong. 1/2nm is 1/2 nm wherevever you are on Earth. It's the lattitude scale you put your dividers against to measure distance, not the longitude scale. DaveP
