Many surveyors of my era, when asked what the longest sight line they have ever made, give the wrong answer simply because they don't think of this as a sight line.
The answer is 430 light years, the object being sighted is Polaris!
Did you know that same sight line is also the longest made by governmental surveying agencies all over the world?
The USC&GS claims the longest sight they have made between two points on the earth's surface is 193 miles long.
What is the longest surveying sight line you have made on the earth's surface?
David C. Garcelon
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