Uploaded October 2023 | Updated September 2026, 1 week ago

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Near the poles, both magnetic compasses and gyrocompasses become increasingly inaccurate due to the converging of the earth's magnetic field and lines of longitude. Before the advent of electronic navigation aids, pilots operating at these high latitudes relied on specialized instruments like the Astrocompass, which uses the position of various celestial objects to determine the bearing of True North.

SOURCES:

http://www.mijnoudespulletjes.nl/pdf/Astrocompassmanual.pdf
prc68.com/I/AC_D500.shtml
samwallermuseum.ca/collections/feature/astrocompass
pge.com/includes/docs/pdfs/about/edusafety/training/pec/toolbox/tll/appnotes/astro_compass.pdf
g4osj.co.uk/Text/Astro%20Compass%20Mk%20II.html
https://www.sundials.co.za/THE%20SUNDIAL%20GOES%20TO%20WAR%20web.pdf
historyofbath.org/images/BathHistory/Vol%2011%20-%2006.%20Burroughs%20-%20Gustav%20Horstmann%20-%20Economic%20Migrant%20and%20Clock%20and%20Watchmaker%20-%201828-1893.pdf
radiomuseum.org/dsp_hersteller_detail.cfm?company_id=14139