 Alright, so here we have a sun path diagram of State College, Pennsylvania. We've developed this in the University of Oregon's website for our local latitude and local longitude time zone UTC minus five hours. That's daylight standard time, not daylight savings time. And I've done a little bit of modification to this to give it a green background. This is not something that normally you would see inside of your normal program. But I want to point out a few things. One is that we see that, as discussed before, the sun rises in the east and the sun sets in the west, right? So we're going to have a progression of the sun across the day from left to right. In this particular case, we start out with east on the left, west on the right, south is denoted by 180 degrees, right? And so the thing that I want to point out here is that here we have December at the bottom and June 21st at the top. So this December 21st is the winter solstice, June 21st is the summer solstice. And in between we have right about March 21st through the 23rd is going to be one of the equinox. The other equinox, of course, is going to happen in September. Only half of the year is shown. The arcs that you're seeing here are all the hours of the day interpreted as solar time. So this is going to be 10 o'clock solar time. We're using a 24-hour system here. So this is going to be 2 o'clock solar time, right? And when I look at this, I see that I have two key points, 90 degrees and 270 degrees. 90 degrees of course is going to be due east and 270 degrees is due west in this particular meteorological standard for the azimuth directions. We see that on the right or on the left side, excuse me, we have the altitude angle. That would be alpha and we're counting down for the zenith angle, the complement to the altitude angle. Let's go back to this east and west. So when does east happen? East happens that due east is 90 degrees, due west is 270 degrees. What's really important here is when does that happen? You see that there's an arc right along here for March 21st and that's really close to the equinox. So during the equinox, we have the sun, that's the only time of the year. So two times during the year when the sun rises due east and sets due west. And if we count the hours, we have one, two, three, four, five, six, exactly six hours in the morning. One, two, three, four, five, six, exactly six hours in the afternoon. So a 12-hour day, our only 12-hour day that's going to happen. Otherwise, all of the rest of this time, if we're looking at... Let's grab a color here. If we're looking at all of this time of the year from December to February and after March. So before March is down here, after March is up here. So we're going to have short days, shorter than 12, and we're going to have longer than 12 hours up in the summertime. It gives you a brief breakdown of what's happening on orthographic projection. This is for State College, of course, as we go further north. We're going to see that our sun charts are going to get lower to the ground. If we were to choose a latitude location that is closer to the equator, we're going to have plots that start to look like this. Actually, they're going to look really kind of funny because they're going to spread out up into the 90-degree space. Because once you're within the tropics, you're going to find that the sun can be to the north or to the south. It's not always in the south as it is when you're beyond the tropics. Anyway, I hope that's a helpful explanation.