Let me set the scene — Page 455, Lesson 447

This is a page from the General Navigation manual that looks like a dense table of numbers — and I want to make sure you understand what you're actually looking at, because it's not random data. This is a sunrise and sunset table, and it's one of the most practical tools you'll use in real navigation. Let me set the scene. The table is organized by latitude bands — you'll see labels like N50, N20, N10, then 0, then S10, S30, and so on. The "N" and "S" stand for North and South latitude, and the number is the latitude in degrees. So N50 means 50 degrees North, S30 means 30 degrees South, and 0 is the Equator. Now, the numbers themselves — they look like a jumble, but they're actually times of day, expressed in hours and minutes. For example, you'll see entries like "18 10" or "17 03" or "16 58". These are times in UTC — Universal Time Coordinated — which is the standard time reference used in aviation, often called Zulu time. So "18 10" means 18 hours and 10 minutes UTC. Here's the key structure: for each latitude band, the table gives you two times per day — one for sunrise and one for sunset. The pattern repeats across the columns, and each column represents a different date or day of the year. So as you read across a row, you're seeing how sunrise and sunset times change day by day at that latitude. Let me give you a concrete example. Look at the N50 row — you'll see a long string like "18 10 18 03 17 57 17 51 17 45 17 39 17 33 17 27 17 22 17 17 17 12 17 07 17 03 16 58 16 55". Each pair is a time. The first entry, 18 10, is the sunrise time on the first date. The next entry, 18 03, is the sunset time on that same date. Then 17 57 is sunrise on the next date, 17 51 is sunset on that date, and so on. So the pattern alternates: sunrise, sunset, sunrise, sunset, across the row. Now watch what happens as you move across the N50 row. The times are decreasing — 18 10, then 17 57, then 17 45, then 17 33, and so on down to 16 55. That tells you the days are getting shorter — the sun is rising later and setting earlier. That's the signature of autumn in the Northern Hemisphere, when daylight hours are shrinking as winter approaches. Now compare that to the S30 row, further down. There you see times like "18 26 18 27 18 29 18 31 18 33 18 36 18 38 18 40 18 42 18 45 18 47 18 50 18 52 18 55 18 58 19 00 19 03". Here the times are increasing — the days are getting longer. That's because it's spring in the Southern Hemisphere at the same calendar date. The same date that brings shorter days to the north brings longer days to the south. That's the seasonal contrast built right into this table. There's also a subtle detail in the numbers themselves. Look at entries like "17 03 17 00" or "16 59" — you'll notice some times are written with a space, like "17 03", and some are written as a single string like "1703" or "1659". That's just a formatting variation in the table — the meaning is identical. "17 03" and "1703" both mean 17 hours and 3 minutes UTC. Now, why does this matter for you as a pilot? Because sunrise and sunset times determine whether you're operating in daylight or darkness, and that has real regulatory consequences. Many flight operations — especially under Visual Flight Rules, or VFR — are restricted to daylight hours. Knowing the exact sunrise and sunset time at your position tells you when you must be on the ground, or when you need to switch to instrument conditions. This table is how you look that up quickly without a computer. Let me also point out the 0 row — the Equator. Look at the entries there: "18 09 18 09 18 09 18 09 18 09 18 09 18 10 18 10 18 11". The times are almost constant — barely changing at all. That's the signature of the Equator, where day length is essentially 12 hours all year round. The sun rises and sets at nearly the same time every day, because the Equator doesn't experience the seasonal tilt the way higher latitudes do. So here's how you'd actually use this in practice. You find your latitude band — say you're at 45 degrees North, you'd use the N50 row as your closest reference. You find the date column you need. You read the sunrise time and the sunset time for that date. Those are your daylight boundaries in UTC. You convert to your local time if needed, and you know exactly when you can legally and safely operate under VFR. One more thing to notice — the table is symmetric in a way. The N50 row shows decreasing times, and the S30 row shows increasing times, but they're moving in opposite directions. That's the seasonal mirror. When it's autumn in the north, it's spring in the south, and this table captures both simultaneously because it covers both hemispheres on the same page. So when you look at this page, don't see random numbers. See a latitude-by-date grid of sunrise and sunset times in UTC, with the N rows showing Northern Hemisphere seasons and the S rows showing Southern Hemisphere seasons, and the Equator row showing near-constant 12-hour days. That's the whole story of this table, and it's a tool you'll reach for whenever you need to know your daylight limits.