First, look at the top — Page 451, Lesson 436

I want to walk you through this sunrise table, because it's one of the most practical tools you'll use in general navigation. This is a table that gives you the time of sunrise at various latitudes, for specific dates in August, September, and October. Let me show you exactly how to read it, because the layout is very specific. First, look at the top. The table is headed "SUNRISE." The columns are dates. You'll see August 15, 18, 21, 24, 27, 30, then September 2, 5, 8, 11, 14, 17, 20, 23, 26, 29, and then October 2. So the columns run across the page in date order, and each column gives you the sunrise time for that date. Now, the rows. The left-hand column is labelled "Lat." — that's latitude. The values run from N 72 degrees at the top, down through N 70, N 68, N 66, N 64, N 62, N 60, N 58, N 56, N 54, N 52, N 50, N 45, N 40, N 35, N 30, N 20, N 10, then 0 (the equator), then S 10, S 20, S 30, and S 35. So the table covers both northern and southern latitudes. Here's the key thing about the time format. Each sunrise time is given in hours and minutes — you'll see pairs like "02 21" or "04 13." The first number is the hour, the second is the minutes. So for N 72 on August 15, sunrise is at 02 hours 21 minutes. And notice the times are in UTC — this is a standard table, so the times are given in Universal Time Coordinated, not local time. That's important for navigation, because you'll be working in UTC. Let me walk you through a few specific values so you can see the pattern. At N 72 degrees on August 15, sunrise is 02:21. By August 18, it's 02:41. By August 21, 02:59. You can see the times getting later as the month progresses — that's the seasonal change. At N 60 on August 15, sunrise is 04:13. At N 50 on the same date, it's 04:49. At N 20, it's 05:40. At N 10, 05:51. At the equator, 0 degrees, sunrise on August 15 is 06:01. Now here's a really important pattern to notice. As you go from high northern latitudes down toward the equator, the sunrise times get later — from 02:21 at N 72 to 06:01 at the equator. That's because of the Earth's tilt and the season. And then, as you cross into the southern hemisphere, look at what happens. At S 10 on August 15, sunrise is 06:11. At S 20, it's 06:22. At S 30, 06:34. At S 35, 06:41. So the times keep getting later as you go further south. The pattern continues smoothly across the equator. Now, notice something else about the table. The times are not perfectly uniform. Look at the equator row: 06:01 on August 15, then 06:01, 06:00, 05:59, 05:58, 05:57, 05:56, 05:55, 05:54, 05:53, 05:52, 05:51, 05:50, 05:49, 05:48, 05:47, 05:46. So at the equator, sunrise is getting slightly earlier as we move from August into September and October. That's the seasonal variation even at the equator. But now look at the high northern latitudes. At N 72, the times go from 02:21 in mid-August to 06:21 by October 2. That's a huge change — over four hours later. The higher the latitude, the more dramatic the seasonal change in sunrise time. That's a critical concept for navigation: at high latitudes, the sun's behaviour changes very rapidly with the seasons, and you need this table to know exactly when sunrise will occur. Let me also point out how the table handles the minutes. You'll see values like "02 21" and then "02 41" — the minutes are given as two digits. And in some rows, you'll see the minutes column has values that skip around a bit, like at N 70 where you see 02 54, 03 09, 03 23, 03 38, 03 51, 04 04, 04 17, 04 30, 04 42, 04 54, 05 06, 05 18, 05 30, 05 42, 05 54, 06 06, 06 18. The increments aren't perfectly even — they vary because of the Earth's orbital mechanics, but the table gives you the exact value for each date and latitude. Now, how do you actually use this in navigation? You'd look up your latitude — or the latitude of the point you're interested in — and then find the date column. The intersection gives you the sunrise time in UTC. This is useful for planning flights, for knowing when it will be light, for calculating things like twilight, and for understanding the sun's behaviour at your position. One more thing to notice: the table only goes down to S 35 degrees. So if you're operating at latitudes further south than that, this particular table won't cover you — you'd need a different source. And the northern coverage goes up to N 72. So the table covers the latitudes most relevant for typical flight operations. Let me also mention the format of the times more carefully. When you see "02 21," that's 02 hours and 21 minutes. When you see "06 01," that's 06 hours and 01 minute. The hour is always two digits, and the minutes are always two digits. So "05 51" is 05:51, and "06 41" is 06:41. Now, let me highlight one more pattern that's really important. Look at the N 72 row across the whole table: 02:21, 02:41, 02:59, 03:17, 03:33, 03:49, 04:04, 04:18, 04:33, 04:47, 05:00, 05:14, 05:27, 05:41, 05:54, 06:08, 06:21. The increments between dates are roughly 15 to 20 minutes early on, then they slow down a bit. Compare that to the N 10 row: 05:51, 05:51, 05:51, 05:51, 05:51, 05:51, 05:51, 05:51, 05:50, 05:50, 05:50, 05:50, 05:49, 05:49, 05:49, 05:49, 05:49. At N 10, the change is only a minute or two across the whole period. So the rate of change of sunrise time is much greater at high latitudes than near the equator. That's a fundamental relationship you need to internalise. So, to summarise what this table gives you: for any latitude from N 72 to S 35, and for any date from August 15 to October 2, you can find the exact UTC time of sunrise. You read across the date columns and down the latitude rows, and the intersection gives you your answer. The times are in hours and minutes UTC, and the table shows you how sunrise varies with both latitude and date. That's the complete picture of this table.