[AZ-Observing] Re: By The Light of The Southerly Moon
- From: Tom Polakis <tpolakis@xxxxxxx>
- To: az-observing@xxxxxxxxxxxxx
- Date: Wed, 27 Apr 2005 17:01:28
Before I had desktop planetarium software, I used to wonder why the math
didn't work out. The southermost point on the ecliptic is 23.50 degrees
south of the equator. And the moon's orbital inclination is 5.15 degrees.
Adding the two numbers gives the farthest southerly declination of the
moon: 28.65 degrees, right? How can it be farther south than that?
I learned that this only applies for the center of the earth. The radius
of the earth is large enough to shift the moon's declination due to parallax.
Voyager III matches the JPL Horizons' moon declination for Phoenix. Here's
what it shows for other latitudes at 4 a.m. MST tomorrow:
60 deg. N -29d 18'
30 deg. N -29 10
0 deg. -28 47
30 deg. S -28 17
60 deg. S -27 47
Tom
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