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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Moon HP and Earth SD
From: Lars Bergman
Date: 2018 May 13, 13:25 -0700
From: Lars Bergman
Date: 2018 May 13, 13:25 -0700
Further to my previous post, I found in Pettersson's "Lärobok i navigations-vetenskapen", 4th edition 1876: "En himmelskropps horisontal-parallax är icke annat än den vinkel, varunder jordens radie från honom skulle synas. Från månens medelpunkt synes således jordens radie, på medelafståndet, under en vinkel av 57'2". " This is, in my translation "The horizontal parallax of a heavenly body is nothing else than that angle, which the earth's radius would be seen from him. Thus from the center of the moon, at mean distance, the earth's radius would be seen at an angle of 57'2". "
This was more than 140 years ago.
Lars
