Opinion

Twilight’s first gleaming

Maine is the easternmost state in the U.S., and as such, it receives the sun’s first rays, every single day of the year. But exactly where in our state do those first rays land? Well, that changes, depending on the time of the year.

Over the years I have heard people lay claim to different spots for the first rays of the new day. Some say Mars Hill, some say Cadillac Mountain on MDI, others say it’s someplace way Down East. Well, it turns out that everyone is right, but only at certain times of the year.

In January, February, much of October, November and December, the first rays fall upon Cadillac Mountain, on Mount Desert Isle. Through much of March, and then mid-September into early October, the first golden rays illuminate West Quoddy Head in Lubec, which indeed, is way Down East.

Then, from late March through mid-September (so for about another three weeks) those first rays strike Mars Hill Mountain, right here in The County. So if you are having visitors up over the next three weeks, you all can go up there and take in the very first rays in the U.S.A.

The reason for this “moving around” of the sun’s first rays is that the sun rises in different places at different times of the year. This is due to the fact that we orbit the sun on a tilted axis. There are many, easy-to-find diagrams of this for those interested.

On the summer solstice, June 21, the sun rises in the northeast. On the equinoxes, both spring and fall, it rises in the east. Then on the winter solstice, Dec. 21, it rises in the southeast.

Not only does the position of sunrise and sunset change over the course of the year, so too does the sun’s height in the sky. To find out how high the sun gets above the southern horizon at its highest point each day (known as solar noon), there is a latitude-dependent formula which you can use. It’s (90 – (your latitude) + declination). Think of declination as the latitude where the sun is shining directly overhead on a given day. The declination latitudes for the two solstices and two equinoxes are: June 21 (summer solstice): +23.5(N); Dec. 21 (winter solstice): -23.5(S) (southern latitudes are given the “-” sign in this formula). Both the autumn equinox (Sept. 21) and the spring equinox (March 21) have values of zero (the sun is shining over the equator on those dates).

Presque Isle’s latitude is about 46.7 North (The equator is 0 and the North Pole is 90). So Presque Isle is a bit, but only a bit, closer to the North Pole than to the equator. To make the math easier for our equation, let’s round Presque Isle’s latitude to 46.5, and now let’s plug into the equation for the four dates I gave above. We find that at its maximum elevation above the southern horizon, the sun is 67 degrees above the southern horizon at solar noon on June 21, 43.5 degrees above the southern horizon at solar noon on September 21, only 20 degrees above the southern horizon at solar noon on December 21, and then back to 43.5 degrees above the southern horizon at solar noon on March 21. 

Again, solar noon is the sun’s highest point above the southern horizon in its transit across the sky each day. 

The varying sun paths over the course of the the year have a dramatic impact on daylight received. At Caribou it maxes at 15 hours, 53 minutes, while the shortest daylight is only 8 hours, 32 minutes, a difference of 7 hours and 21 minutes.

Knowing where the sun rises and sets, as well as how high it is in the sky, it very useful when looking at where you and your family are going to live. You can find out which rooms get direct sunlight at different times of the year. Maybe you’ve always wanted a sunny breakfast nook in winter. Now you can know if the house you are looking at has one.

Ted Shapiro holds the Broadcast Seal of Approval from both the American Meteorological Society and the National Weather Association. An Alexandria, Va. native, he has been chief meteorologist at WAGM-TV since 2006. Email him at tshapiro@wagmtv.com.

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