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Re: Longitude by compass variation
From: Robin Stuart
Date: 2025 Jun 18, 06:20 -0700
From: Robin Stuart
Date: 2025 Jun 18, 06:20 -0700
Lars,
You wrote "Every time there was a good opportunity to do so, e.g. when the Polar Star was visible, observations of variation were taken to determine the longitude."
This might be a silly question but do we know if they corrected for the azimuth of Polaris? I find that for an observer at latitude, L, a circumpolar star at declination, δ, reaches a maximum azimuth Zmax given by sin Zmax = cos δ / cos L. In 1850 the declination of Polaris was about 88.5° and at the latitude of Newfoundland of 55°N the azimuth for Polaris would vary over a range of 5.2°,
Regards,
Robin
