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All right, and now we got the same location.
Again, the location is going to be State College
Pennsylvania.
Solar time is going to be minus 5
hours, relative to UTC.
And latitude longitude is 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 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 at the sky
with a fish eye 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 June time.
And the progression of the day is going to be across the arc,
again, from left to right, the 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 probably a lot more apparent here that the length
of the December 21st day is much shorter of an arc then
the summer solstice on June 21st.
Again, our arrows 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.
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 in a zenith angle going down or
going outward, two rings.
An altitude angle coming up or inward, basically coming along
the edge of that sky dome.
And any one of these points of these green arcs are going to
be a combination of an altitude angle
and a azimuth angle.
And here the azimuth angles are going to rotate from North
which is zero degrees.
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 are do 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 south.
Again, 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 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 of the only
official day that you're going to have
twelve 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, whereas everything in
the winter months are going to be shorter.
And 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 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 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 angle.