The chapter opens with Sunrise and Sunset on page 421 — Page 422, Lesson 381

We're starting Chapter 26, which is all about time — specifically, how we define and use time in navigation. The chapter is called "Time (3)," and it covers three main topics: Sunrise and Sunset, the methodology behind Sunrise and Sunset Tables, and Twilight. Then there are two sets of practice questions, answers, and an Air Almanac extract at the end. Let me walk you through the structure first, because it tells you what you'll be expected to master. The chapter opens with Sunrise and Sunset on page 421. That's the core concept — when exactly does the Sun rise and set, and how do we define those moments for navigation purposes. Then on page 422, we get into the methodology for using Sunrise and Sunset Tables. This is the practical part — how you actually look up and apply these times. After that, on page 424, we cover Twilight, which is the period around sunrise and sunset when the Sun is below the horizon but still illuminating the sky. Now, here's something important for you as a professional pilot. These aren't just academic definitions. Sunrise, sunset, and twilight times directly affect your flight planning — they determine when you need navigation lights, when you can legally fly under visual flight rules, and how you calculate your fuel and timing. So this chapter is giving you the precise, standardized definitions that the regulations and your flight planning software are built on. The chapter then has Questions 1 on page 430 and Questions 2 on page 431, with Answers 1 and Answers 2 both on page 433. And finally, there's an Air Almanac Extract on page 436. The Air Almanac is a publication that gives you precise astronomical data — including sunrise and sunset times — for any position on Earth at any date. You'll learn how to extract the data you need from it. So the flow of this chapter is: first you learn the theory of sunrise and sunset, then you learn how to use the tables to find those times, then you learn about twilight, and finally you practice with questions and learn to use the Air Almanac. Let's start with the first topic — Sunrise and Sunset — and I'll explain exactly how we define those moments and why the definition matters for navigation.