So the rows are your latitude bands — Page 444, Lesson 409

This is the sunrise table for the month of February through April, and it's the heart of how we compute daylight for navigation. Let me walk you through exactly how to read it, because this is a table you'll use operationally. The table is organised by latitude, in degrees north and south, down the left-hand side. You'll see N 72, N 70, N 68, all the way down to N 20, N 10, then the equator at 0, then S 10, S 20, S 30, S 35, S 40, S 45. So the rows are your latitude bands. Across the top, the columns are dates. February 16, 19, 22, 25, 28, then March 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, then April 2. Each column gives you the time of sunrise for that latitude on that date. Now, the times are in hours and minutes, and they're given in two rows for each latitude. The top row is the hour, the bottom row is the minutes. So for example, at N 72 on February 16, you read 08 hours and 51 minutes — that's 08:51. On February 19, 08:33. And so on. Here's the key thing to notice: the times are in UTC, not local time. That's critical for navigation, because we always work in a common time reference. And the table gives you sunrise, not sunset — this particular table is for sunrise only. Now let's look at the pattern. At high northern latitudes, like N 72, sunrise in mid-February is around 08:51, and it gets earlier as spring progresses, down to about 04:53 by early April. That's a huge change — nearly four hours over the period. The higher the latitude, the more dramatic the change. At the equator, at 0 degrees, sunrise is essentially constant — around 06:00 to 06:01 throughout the whole period. That's because the equator has almost no seasonal variation in day length. Now here's the interesting part — look at the southern latitudes. At S 10, sunrise in February is around 06:02, and it gets slightly later as we move into April, reaching about 06:04. At S 30, it's 05:41 in mid-February, getting later to about 06:11 by early April. So in the southern hemisphere, the trend is reversed — sunrise gets later as we move from February into April, because that's autumn there. Notice also the minute values — they're not all two digits. Some are single digits, like 5, 6, 7, 8. That's just the table omitting the leading zero. So a "5" in the minutes row means 05 minutes. One more thing to note: the table is interpolated. If your latitude falls between the listed values, or your date falls between the listed dates, you'll need to interpolate between the nearest entries. For example, if you're at N 55, you'd interpolate between the N 50 and N 60 rows. And if your date is February 20, you'd interpolate between February 19 and February 22. So the practical use: you know your latitude and your date, you enter the table, you read the sunrise time in UTC. That gives you the start of daylight, which you'll use for planning things like departure times, fuel planning, and understanding how much daylight you have available for your flight. That's the sunrise table