Let me walk you through exactly what you're looking at and why it matters — Page 440, Lesson 403

This is a table of sunrise and sunset times — a critical piece of navigation data for a professional pilot. Let me walk you through exactly what you're looking at and why it matters. First, the big picture. In general navigation, we need to know when daylight begins and ends at any point on Earth. This matters for several operational reasons: planning flights that must land before dark, determining when you need to carry navigation lights, and — most importantly for instrument-rated pilots — knowing when you're operating under "night" conditions, which changes your legal equipment and currency requirements. This table gives you those times. Now, let's decode the structure. The table is organized by latitude, and you'll see latitude values running down the left side — 30, 42, 64, 27, 37, 17, 10, 20, 35, 45, 50, 54, 56, 58, and S60. That "S60" at the bottom is South latitude 60 degrees. The numbers running across the top — 14, 15, 16, 17, 18, 19, 20, 21 — those are hours of the day, in 24-hour time. So the grid works like this: each row is a latitude, each column is an hour, and the numbers inside the grid are minutes. When you combine the hour from the top with the minutes from the cell, you get a time of day. For example, if you see "14 41" in a cell, that means 14:41, or 2:41 PM. Here's the key thing to understand about how these tables are built. Look at the first row — latitude 30. You'll see a sequence: 14 14 14 19 14 25, then 33 14 41 14 49 14 59 15 08 15 18. What's happening is that the table is giving you the time of sunrise and sunset for each day of the month. The times progress day by day — sunrise gets earlier or later, sunset gets earlier or later — as the seasons change. Let me show you a concrete example. Look at the row for latitude 30 again. The first entry is 14 14 — that's 14:14. Then 14 19, 14 25, 14 33, 14 41, 14 49, 14 59, 15 08, 15 18. Each of these is a successive day's time. So on day one, the event happens at 14:14; on day two, 14:19; day three, 14:25; and so on. The times are creeping later by roughly 5 to 8 minutes per day. Now, here's the critical part for you as a pilot. Notice how the times increase as you go down the rows — from latitude 30 down to latitude 60. At latitude 30, you see times around 14:14 to 15:18. By the time you get to latitude 60, you're seeing times like 21:25, 21:23, 21:20. That's the effect of latitude on daylight hours. The higher your latitude — the closer you get to the poles — the longer the days are in this season, so sunrise is earlier and sunset is later. And look at the bottom row: S60, South latitude 60. The times there — 21 25, 21 23, 21 20, 21 17, 21 13, 21 08, 21 03, 20 58, 20 51, 20 45, 20 38, 20 30, 20 23, 20 15, 20 07, 19 59, 19 50 — those are decreasing. That's because in the Southern Hemisphere, the seasons are reversed. While the Northern Hemisphere is heading into summer with longer days, the Southern Hemisphere is heading into winter with shorter days. So sunset times are getting earlier. Now, here's a subtlety you need to catch. Look at the row for latitude 10. You'll see: 18 06 18 08 18 09 18 10 18 11 18 13 18 14, then 15 15 16 17 17 17 18 18 18 18, then 10 24 25 26 27 28 29 29 29 30 30 30 30 29 29 28 27 26. Notice how the times increase, then peak, then decrease. The times go up to 18:14, then the numbers 15, 16, 17, 17, 17, 18, 18, 18, 18 — those are still increasing. Then they hit a peak around 30, and then start coming back down: 29, 29, 28, 27, 26. That's the solstice effect. The days get longer, reach a maximum around the summer solstice, and then start getting shorter again. The table captures that turning point. Let me also point out the minute-by-minute progression within each day. Look at latitude 45: 19 50 19 50 19 49 19 49 19 48 19 46 19 44 19 42, then 40 37 34 30 27 23 18 14 09 50, then 20 12 20 12 20 11 20 10 20 08 20 06 20 03 20 01 19 57 19 54. The times are decreasing — 19:50, 19:49, 19:48, 19:46, 19:44, 19:42, 19:40, 19:37, 19:34, 19:30, 19:27, 19:23, 19:18, 19:14, 19:09, 19:50 — wait, that last one jumps. Let me re-read that. Actually, look more carefully. The row for latitude 45 reads: 19 50 19 50 19 49 19 49 19 48 19 46 19 44 19 42, then 40 37 34 30 27 23 18 14 09 50, then 20 12 20 12 20 11 20 10 20 08 20 06 20 03 20 01 19 57 19 54. So the first block is 19:50, 19:50, 19:49, 19:49, 19:48, 19:46, 19:44, 19:42. Then the next block: 19:40, 19:37, 19:34, 19:30, 19:27, 19:23, 19:18, 19:14, 19:09, and then 19:50 — no wait, that "50" at the end of that block is actually the start of the next hour. Let me re-read. The row continues: 40 37 34 30 27 23 18 14 09 50 — so that's 19:40, 19:37, 19:34, 19:30, 19:27, 19:23, 19:18, 19:14, 19:09, and then the "50" is actually 19:50? No — that doesn't make sense. Let me look at the structure again. Actually, I think I'm misreading the layout. The table has hour labels at the top, and the minutes are grouped under each hour. So under the hour "19", you have the minutes 50, 50, 49, 49, 48, 46, 44, 42, 40, 37, 34, 30, 27, 23, 18, 14, 09. Then under the hour "20", you have 12, 12, 11, 10, 08, 06, 03, 01, and then back under "19" you have 57, 54. So the times are: 19:50, 19:50, 19:49, 19:49, 19:48, 19:46, 19:44, 19:42, 19:40, 19:37, 19:34, 19:30, 19:27, 19:23, 19:18, 19:14, 19:09, then 20:12, 20:12, 20:11, 20:10, 20:08, 20:06, 20:03, 20:01, then 19:57, 19:54. So the times are decreasing — sunset is getting earlier each day. That's the autumn trend at latitude 45 in the Northern Hemisphere. Here's the operational takeaway for you. When you're planning a flight, you look up your latitude — or more precisely, the latitude of your departure and destination — and you read across the row to find the sunrise and sunset times for the date you're flying. You interpolate between the daily values if your date falls between two entries. Then you apply that to your flight planning: you ensure you'll land before sunset if you're not night-current, or you plan for night operations if you are. And one more critical point: these tables are typically published for a standard meridian — usually Greenwich or a zone meridian — and you must apply your longitude correction to convert the tabulated time to your actual local time at your specific longitude. The table gives you the time at the reference meridian; your actual position east or west of that shifts the times by 4 minutes per degree of longitude. So when you see a table like this in your navigation manual, you're looking at a daily sunrise/sunset schedule organized by latitude, with times in 24-hour format, progressing day by day, showing the seasonal lengthening or shortening of daylight, and the latitude effect on day length. That's the data you'll use to make your operational decisions about day versus night operations.