Home > Concepts, Seasons, The Moon > 06/22/2015 – Ephemeris – The summer full moon and the winter Sun trade places

06/22/2015 – Ephemeris – The summer full moon and the winter Sun trade places

June 22, 2015

Ephemeris for Monday, June 22nd.  Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32.   The Moon, 2 days before first quarter, will set at 1:04 tomorrow morning.  Tomorrow the Sun will rise at 5:57.

Summer’s here, and it’s a few days before the latest sunset and latest end of twilight.  It might be instructive to check out the height of the moon over the next two weeks or so.  The moon is heading south in front of the Sun.  The Sun besides its apparent westward motion during the day caused by the Earth’s rotation also moves about twice its diameter each day eastward against the stars caused by the earth’s motion in its orbit of the Sun.  Around July 1st, the moon will be about where the Sun will be next winter solstice, 4 days before Christmas.  Actually it will be about 8 moon widths above where the Sun will be because its orbit is tilted a bit to the Earth’s.  But it will serve as an illustration of the seasonal difference.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Summer full moon

The full moon nearest the summer solstice. The full moon appears near where the sun would appear low in the south at the winter solstice. The bottom red line is the ecliptic, the path of the Sun. Created using Stellarium.

Moon near the winter solstice

The full moon nearest the winter solstice. The full moon appears near where the sun would appear high in the south at the summer solstice. The top red line is the ecliptic, the path of the Sun. Created using Stellarium.

The Moon’s orbit has a slight tilt of a bit more than 5 degrees from the ecliptic, or plane of the Earth’s orbit of the sun.  The crossing point is called a node.  In the bottom image the node near the western horizon is called the descending node due to the fact that the Moon is heading south of the ecliptic.  When the Sun and Moon are near the same node the Moon will be new and we have a chance for a solar eclipse.  When at opposite nodes, a lunar eclipse.  The nodes slowly slide westward slowly one revolution in about 18.6 years, which causes eclipse seasons, about 6 months apart to occur a bit earlier each year.

Categories: Concepts, Seasons, The Moon Tags: , , ,
%d bloggers like this: