Celestial Navigation for Dummies

Sources:
Celestial Navigation for Yachtsmen
Don't leave shore without this easy-to-use celestial favorite navigation primer--it could save your life!
A bestseller for over 65 years, Celestial Navigation for Yachtsmen is a model of simplicity and clarity. The only mathematics involved are addition and subtraction, which explains why this book has truly earned its reputation for admirable conciseness and for making a tricky subject easy to understand.

William F. Buckley Jr. - Celestial Navigation Simplified N203DVD
https://youtu.be/b5dIJsMCd2I.

Sextant to Line of Position - A Complete Sight Reduction from an Offshore Sailing Race
https://youtu.be/vmpzm-1qqrI.