The table is arranged by latitude bands — Page 447, Lesson 420

I want to walk you through what you're looking at here, because on the surface it's just a wall of numbers — but this is actually one of the most important tables in all of general navigation. This is a sunrise and sunset table, and it's the kind of thing you'll use to plan when you can legally and practically fly, especially for night flying rules and for estimating daylight at your destination. Let me first tell you what the structure of this table is, because once you see the pattern, the numbers stop being random. The table is arranged by latitude bands. You'll see labels like N 50, N 20, N 10, S 10, S 30, S 52, S 60 — those are the latitudes. N means north of the equator, S means south. So this table covers a wide range of latitudes, from 50 degrees north down to 60 degrees south. Each row is a different latitude, and the columns are dates across the year. Now, the key thing to understand: the numbers you see, like 18 56, 19 02, 20 04 — those are times of day, in hours and minutes, on the 24-hour clock. So 18 56 means 6:56 in the evening, 20 04 means 8:04 in the evening. These are the times of sunset — the moment the sun goes below the horizon. But wait — I need to be careful here, because this table actually contains two different sets of information, and you can see them if you look at the pattern of the numbers. Look at the top portion of the table, around the N 50 row. The times there are in the 19 00 to 20 00 range — early evening. Those are sunset times. As you move through the columns, you'll see the times get later and later — 19 06, 19 10, 19 15, 19 20, 19 26 — and then they start coming back down. That's the seasonal variation: in summer, the sun sets late; in winter, it sets early. Now look at the bottom portion of the table, the S 10 through S 60 rows. The times there are in the 17 00 to 18 00 range — that's earlier in the evening. And here's the critical thing: those are sunrise times, not sunset times. Because when you're in the southern hemisphere, the seasons are reversed, and the table is giving you the morning times for those latitudes. So this single table gives you both sunrise and sunset, depending on which latitude band you're reading. The northern latitudes give you sunset times; the southern latitudes give you sunrise times. That's the first big distinction you need to hold in your head. Let me walk you through a specific example so you can see how to read it. Take the N 50 row — that's 50 degrees north latitude, roughly the latitude of places like southern England. Look at the first few entries: 19 06, 19 10, 19 15, 19 20, 19 26, 19 31, 19 36, 19 41, 19 46, 19 51, 19 56, 20 01, 20 07, 20 12, 20 16, 20 21. Do you see the pattern? The times are increasing — the sun is setting later and later. That tells you these columns are moving from spring into summer. The sun sets at 19:06, then 19:10, then 19:15 — each column is a few days later in the year, and the days are getting longer. Then look further along: 20 21, and then the times start decreasing — 20 16, 20 12, 20 07, 20 01, 19 56, 19 51. That's the turn after midsummer, when the days start getting shorter again. So the table lets you track the lengthening and shortening of daylight through the year at each latitude. Now here's a really important detail I want you to notice. Look at the N 20 row — 20 degrees north. The times there are 18 37, 18 38, 18 39, 18 40 — they're almost constant. They barely change at all across the columns. That's because 20 degrees north is close to the equator, where the length of daylight is nearly the same all year round. The sun rises and sets at almost the same time every day. That's a beautiful demonstration of how latitude controls the seasonal variation in daylight. Now let me show you the southern hemisphere rows, because they work differently. Look at the S 10 row — 10 degrees south. The entries are 18 25, 18 23, 18 21, 18 20, 18 18, 18 17, 18 16, 18 14, 18 13, 18 12, 18 11, 18 10, 18 09, 18 09, 18 08, 18 08. Here the times are decreasing — and remember, these are sunrise times. So the sun is rising earlier and earlier. That means the days are getting longer — but in the southern hemisphere, that happens at a different time of year than in the north. When it's summer in the north, it's winter in the south, and vice versa. So the same table, read for southern latitudes, gives you the opposite seasonal pattern. Now look at the S 30 row — 30 degrees south. The entries are 18 20, 18 16, 18 13, 18 10, 18 06, 18 03, 18 00, 17 57, 17 54, 17 52, 17 49, 17 47, 17 45, 17 43, 17 41, 17 39. Again, decreasing — the sun is rising earlier. And notice the times are getting into the 17 00 range — 17:57, 17:54, 17:52. That's quite early in the morning for a sunrise. Now here's a subtle but crucial point. Look at the S 52 row and the S 60 row — those are high southern latitudes, 52 and 60 degrees south. Look at the entries: 18 17, 18 11, 18 04, 17 57, 17 51, 17 45, 17 39, 17 33, 17 27, 17 22, 17 16, 17 11, 17 07, 17 02, 16 58, 16 54. The times are dropping fast — from 18:17 all the way down to 16:54. That's a huge change across the columns. At high latitudes, the seasonal variation in daylight is much more dramatic than at low latitudes. Near the poles, the sun rises very early in summer and very late in winter. That's why the numbers swing so widely at S 60 compared to N 20. And look at the S 60 row more carefully: 18 17, 18 09, 18 00, 17 51, 17 43, 17 35, 17 27, 17 19, 17 11, 17 04, 16 57, 16 50, 16 43, 16 37, 16 31, 16 26. From 18:17 down to 16:26 — that's nearly two hours of change across the columns. At 60 degrees south, the sun's rising time shifts dramatically through the year. That's the extreme end of the table. Now, why does this matter for you as a pilot? Let me give you the operational picture. When you're planning a flight, you need to know the times of sunrise and sunset for your departure, your destination, and anywhere along your route. This is critical for night flying rules — many aviation authorities define "night" as the period between the end of evening civil twilight and the beginning of morning civil twilight, and the times of sunrise and sunset are the anchors for that calculation. If you're going to arrive after sunset, you need to be rated and equipped for night operations. If you're departing before sunrise, same thing. So this table is your planning tool. You look up your latitude, you find the date column, and you read off the time of sunrise or sunset. Then you can work out how much daylight you have available for your flight, whether you'll be landing in daylight, and whether you need to file for night operations. Let me also point out the structure of the columns, because you'll see the dates are not written out — they're implied by the position. Each column is a specific date, and the columns progress through the year. The table is arranged so that as you read left to right, you're moving forward in time. The times in each row rise to a peak and then fall — that peak is midsummer for that hemisphere. One more thing I want you to notice, and this is a real navigator's detail. Look at the N 10 row — 10 degrees north. The entries are 18 37, 18 37, 18 38, 18 39, 18 40, 18 41, 18 42, 18 43, 18 44, 18 46, 18 47, 18 48, 18 49, 18 51, 18 52, 18 53. The times are increasing — the sun is setting later. But the change is tiny — from 18:37 to 18:53, that's only about 16 minutes across the whole set of columns. Compare that to the N 50 row, where the times swing from 19:06 up to 20:21 and back — that's over an hour of change. So the closer you are to the equator, the less the daylight varies; the closer you are to the poles, the more it varies. That's the fundamental relationship this whole table is built on. Now, let me also make sure you understand the format of the times. You'll see entries like 19 57, 20 04, 20 08 — these are hours and minutes on the 24-hour clock. There's no colon; it's just four digits, or sometimes three digits like 18 09 or 17 03. The first two digits are the hour, the last two are the minutes. So 20 04 is 8:04 PM, 17 03 is 5:03 AM. And you'll notice some entries have a single digit at the end, like 19 58, 20 05, 20 08 — those are still minutes, just written without a leading zero. 19 58 is 7:58 PM, 20 05 is 8:05 PM. Let me also point out the N 45 row, because it's a good middle example. The entries are 18 58, 19 02, 19 06, 19 10, 19 14, 19 18, 19 22, 19 26, 19 30, 19 35, 19 39, 19 43, 19 47, 19 51, 19 55, 19 58. Increasing from 18:58 up to 19:58 — that's a full hour of change. At 45 degrees north, you get a substantial seasonal swing, but not as extreme as at 50 degrees north. And the N 40 row: 18 56, 18 59,