Here's an odd one. "Dee" writes from a Baltimore County Public Library: "On the afternoon of Sept. 12, I will be flying from BWI to Salt Lake City. I want to sit where the sun will not be in my eyes. The location of sunsets in the continental U.S., in different seasons, has always puzzled me, and probably always will. Is there a rule of thumb?"

Let’s see, Dee. You could change your reservation and fly after sunset (7:19 on the 12^th). You could fly east, around the planet, and face the east for the entire flight and miss all the sunsets. You could, of course, pull the shade. Problem solved.

But, if you're like me, you probably like to look out the window at the countryside drifting by. So, here are some thoughts.

You'll be flying almost exactly due west. That means the passenger windows will face either north or south.

Sunsets (and sunrises) during late summer and fall are moving slightly farther south each evening, from their farthest north at the summer solstice in June, to their farthest south at the winter solstice in December.

At the time of the Autumnal Equinox (Sept. 23 this year), the sun rises due east and sets due west. If you were to fly on that date, the sunset would be in the pilots' eyes, but passengers looking north or south wouldn't have a problem. (This assumes a flight plan taking you straight west. Course changes, turns to avoid thunderstorms and maneuvers during climb and descent mean all bets are off. You're on your own.)

But you're flying on the 12th, or 11 days before the equinox. That means sunset will occur a bit north of due west. If you're on the right side of the airplane, you might get some sun in your eyes just at sunset.

On the other hand, you'll probably spend several hours on the plane before sunset. If sunlight is bothersome to you, that presents another problem.

Hypothetically, if you were flying west along the equator, on the equinox (Sept. 23), the sun's path during the afternoon would be from directly overhead at noon, to due west at sunset. You'd never see the sun from a passenger's seat. Eleven days before the equinox, however, the sun, at the equator, would be slightly north of straight up. So, the right side of the plane would be sunnier throughout the flight.

But you'll be flying at a latitude of, roughly, 40 degrees north. That means the sun's path through the sky will be along a path well south of straight up. That means the seats on the left (south-facing) side of the plane will be sunny throughout the flight, until shortly before sunset, when sol will cross in front of the plane and touch down at the horizon slightly north of due west.

The bottom line: Sit anywhere on the right side of the plane until perhaps 30 minutes before sunset. Then, when somebody gets up from a left-hand window seat to use the rest room, steal their seat. Or, rather than raise a ruckus and get yourself locked up, you could a) make your reservation for a right-hand seat, and then pull the shade at sunset; or b) if it's only the sunset that offends you, get a left-hand seat, enjoy the afternoon sunshine and let the sunset fall on those on the right side of the airplane.