[ExI] Happy Solstice!

Lee Corbin lcorbin at rawbw.com
Sun Jun 24 18:15:39 UTC 2007

Spike writes

> Since you take into account the latitude and longitude, your next
> digit of precision on your yardstick experiment comes from taking into
> account the analemma.  This website gives a reasonable explanation:
> http://www.analemma.com/Pages/framesPage.html

That site has a lot great analemms!  Thanks.

> By happy coincidence, the aphelion and perihelion almost correspond with the
> soltices.

Yes, January 3 or so is very close to December 21, and July 4 (if I
remember right) is close to June 22.  A similar nice coincidence that
comes to mind is that at the summer soltice the Earth lies almost
directly between the sun and the center of the galaxy. (Unfortunately
the plane of the ecliptic tilts about sixty degrees or so away from
the galactic plane, so that as our solar system moves in the direction
of Deneb (clockwise around the galaxy) it's as though the it was on
an extreme "rake", like cars have.)

> I am setting up an experiment to mark the pavement on my back patio
> corresponding to the shadow of the peak of the house at exactly noon.
> Of course most days at noon I would not be home, so it will take years
> to get most of the calendar days marked.

I'm sure that you remember to use 1pm in the summers!

> When I do, I will have a figure 8 shaped calendar back there.  Isaac
> will love it.  Is this cool or what?  

Yes, that is *very* neat!

The ancients must have seen a lot of analemmas too.  I wonder how
much they read into the shape of the analemma, especially the part
where the lower part bulges out a lot more than the upper part.


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