Analemma plot since December solstice

Event Date: June 1st

Time: 3:30 PM

Brief

   Since the December solstice, the Sun has moved about 45º north in declination.  I mentioned the cycle of north and south movements of the Sun on our celestial dome based on (a) our revolution around the Sun, (b) the 23 1/2º tilt of our axis.  I am showing where the Sun is each day at the time above.  This shows nearly half of what is called the analemma, which is a figure 8 shape with one loop much larger than the other.  Find out more about the analemmatic sundial as well, linked.  It's neat to see and read about!

The altitude grid is shown to show how high the Sun is above the horizon each day; this is partly dependent on declination of the Sun.

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

   As I mentioned in my first journal of the blog, there would be no declination of the Sun to keep track of if there was no tilt of our axis; the Sun would be at 0º along the celestial equator at all times.  Then again, if we had a nearly-90º axis tilt the way Uranus does, declinations would be at about 180º in difference from one solstice to another, with our poles facing the Sun at the solstices.   As shown for the plot over the last few weeks, the smaller loop is starting to be outlined out.  The markers are 10 days apart.  As I talked about yesterday with the rate of declination slowing down near the time of the solstices, we see the result with the markers; they are more bunched up at two altitudes, and more spread out at the others, where the Sun is at dates closer to the equinox.