New Moon + Node Crossing + Apogee = Solar Eclipse

solar-eclipse-ani    Sunday morning September 13th the Moon, at new Moon phase, will pass between the Earth and the Sun setting up a partial solar eclipse that will be visible from southern Africa toward and then across the Antarctic continent. As with all eclipses the amount and duration of an eclipse is all a matter of timing. The closer the time for the new Moon phase (September 13th 6:41 UT) is to the time of a node crossing (September 14th 4:38 UT) the more centered the Moon will be on the Sun or centered within the Earth’s shadow for a lunar eclipse. The further apart these two times are then the eclipse will probably be a partial eclipse as is the situation for this one. This partial solar eclipse also occurs close to the time for lunar apogee (September 14th 11 UT), the furthest the Moon is from the Earth for that particular orbit.
    Use the this link to Hermit Eclipse web site for additional information about viewing the eclipse. Or check the time of your local sunset and then use the online eclipse-time calculator from NASA to find the timing of the eclipse for your location. Alternately use the Eclipse Calculator at the Time and Date web site.

aug17-ascending-node    On Monday September 14th at 4:38 UT (September 13th at 11:38 pm CDT) our Moon will be crossing the plane of the ecliptic moving north relative to the ecliptic. This is known as the ascending node, one of two intersections the Moon’s orbital path has with the ecliptic. The ecliptic is actually the Earth’s orbit and the Moon’s orbit is inclined about 6o from the ecliptic. So there are two node intersections, the ascending and descending nodes.

sep14-apogee-moon   The Moon reaches apogee, (greatest distance from Earth), this month on Monday September 14th. At that time the Moon will more or less be at a distance of 31.86 Earth diameters (406,464 km or 252,565 miles) from the Earth.
   Does our Moon actually go around the Earth as this graphic shows? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*

*Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

Caution: Objects viewed with an optical aid are further than they appear.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

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