“For practical purposes, I think the way to get the most out of celestial navigation can be stated in five rules. 1. Take five and average. 2. Non decimalis carborundum. (Don’t drown in the decimals.) 3. Keep your altitudes between 10° and 70°. 4. Use a calculator for sight reduction from your DR. 5. Don’t pass up a sight because it doesn’t fit the rules.”