Saturday, July 04, 2009

Aphelion 2009

Aphelion (When an object is at the 'long-end' of it's orbital ellipse occurs in 2009 for this planet at 0402UT 4 July (a couple of weeks after the solstice). Here is a link to a composite picture that of how large the sun appears in the sky at Aphelion and Perihelion. And again as we did for the solstice we can find the location on the earth where it was 12 noon. That would be line of longitude about 15 degrees east of where we found the solstice since this event occurs about an hour earlier than the time of day the solstice occurred. Doing the math we have 4 hours east of Greenwich is 60 degrees East (4*15=60). Then 2 minutes of longitude east of that line brings us to 60o 00' 30" because there are 4 minutes of time for each degree of longitude that comes out to be 1/2 degree of longitude for 2 minutes of time. The graphic above is a google-earth view near that that line of longitude. (I've tilted the planet toward the view to simulate the view from the sun to the earth, I did not put the tropic of cancer right at the middle of the picture but just a bit up from the middle indicating that the 'sun-overhead-at-noon' is now a bit south of where it was on the 21st of June).