 All right, and now we've got the same location Again, the location is going to be state college, Pennsylvania solar time is going to be minus five hours relative to UTC and Latitude launch dudes the same Again, this is a polar plot of the same data that you just saw in the previous video and the north of This plot is is right down at the bottom the south is Up at the top and I do this in this particular case just to keep the arcs in the same general direction But you're going to notice some differences here. One is that the June arc is at the bottom Whereas the December arc is at the top so this polar projection is what you would get if you were effectively lying on the ground and Looking up at the sky with a fisheye lens and then trying to project that flat so we see here that we've got the arcs of the day the morning begins over here the Evening ends over here right in in June time and the progression of the day is going to be across The arc again from left to right same thing as we had before Left to right in the winter months as well But here you're really seeing the differences in the length of the day It's it's probably a lot more apparent here that the length of the December 21st day Right is much shorter of an arc Than the summer solstice on June 21st Again our arrows Are just just pointing out these green arcs are days and the red Lines are the hours of the day in solar time so that This top location here at 90 degrees is going to be the top of the sky the zenith So the zenith angle is basically any angle down from here to One of these circles right whereas the altitude angle is Going to be the angle up From the ground which is going to be in our case the edge of the ring up so we're going to see a In a zenith angle going down or going outward to outward rings an altitude angle coming up Or inward basically coming along the edge of that sky dome right and Any one of these points of these green arcs are going to be a combination of an altitude angle and a zenith angle or excuse me and an altitude angle and a Asimuth angle and here the Asimuth angles are going to rotate from north which is zero degrees So north right here is zero degrees Rotating along to plus 30 plus 60 to finally when we're due east we are at 90 degrees when we're due west We're at 270 degrees south in this case is Going to be 180 degrees so the azimuth rotates around clockwise and 180 degrees is in the meteorological standard going to be south Again the I want you to pay attention to the one day of the year When the Sun rises due east and sets Due west and that's going to be around this March 21st through the 23rd It's a kind of a flexible date depending on the year, but it basically is defined as the day when within which the equinox occurs and so It's going to be one of the few days that are the only official day that you're going to have 12 hours of sunlight so we can count again one two three four five six hours in the morning That's going to mirror to the six hours in the evening making it a 12 hour day and again That means that we're going to have everything in The summer is going to be longer Right, whereas everything in the winter months Are going to be shorter right and That's that's the flip that I'm talking about in the notes that the arcs flip Back and forth so long days are on the bottom short days are on the top or the hole or short days are towards the south This should make sense when we think about the fact that the Sun is low in the sky Low in the sky is going to be closer to the these outermost rings The Sun is low in the sky in the winter The Sun is high in the sky Especially around the noon hour during the summer and you're seeing that right here is that the closer I am to this center ring the closer I am to Right here Which is 90 degrees the higher in the sky that I am and so in the winter time. I'm close to the perimeter which is close to Zero degrees altitude angle this up at the top is close to 90 degrees altitude day. All right