 
    By Rod Hill on 2013-06-23
We lucked out and got to see little bit of the "Supermoon" last evening. The peak viewing will be tonight when the full moon rises at 9:16 p.m. But, as you likely know, solid cloud cover is expected to cover the show. Here is all you would ever want to know about what appears to be the largest moon of the year, courtesty of Jim Todd, OMSI Director of Space Science Education:
June's full moon takes place at 4:32 a.m. PDT on Sunday, June 23  It 
is called the Strawberry Moon; but it can also be called the Rose Moon 
or Honey Moon. When we look at the full moon on Sunday, it will be just 
221, 824 miles away making it the Moon's closest approach to Earth in 
2013.
 
Full moons vary in size because of the elliptical (oval) shape of the 
Moon's orbit. Perigee, or the Moon's closest approach Moon to Earth is 
about 31,068 miles closer to Earth than the its apogee or farthest 
distance. The Moon's distance at perigee changes by 3% over a period of 
18.6 years, but in general while at perigee, a full moon would appear 
about 14% bigger and 30% brighter than a corresponding full moon at 
apogee, but it's not really all that much more dramatic than a regular 
full moon.
 
In March 2011, the full moon was less than one hour away from perigee, a
 near-perfect coincidence that happens about every 18.6 years.  On May 
2012, the full moon was a minute of reaching actual perigee position.  
The point of the moon’s full phase at 4:32 am PDT in June 2013, and 
perigee at 4:09 am PDT, fall within an hour of each other.  On August 
2014, the full moon and perigee will be just 3 miles closer to Earth.
 
Before 2011, the comparable biggest/closest full Moon was March of 1993,
 and presumably the next comparably large full Moon will be 18.6 years 
from then sometime in late 2029.
 
Many are calling this full moon the "Supermoon," blaming it for dramatic
 land and ocean tides which trigger earthquakes. The tides are greatest 
during full and new moons, when the sun and moon are aligned either on 
the same or opposite sides of the Earth.  A very small correlation 
exists between full or new moons and seismic activity, because the 
stronger tidal forces caused by the alignment of the sun and moon puts 
added stress on tectonic plates. However, seismologists have found no 
evidence connecting lunar perigees to heightened seismic activity. 
Instead, the Earth constantly stores up energy and releases it any time 
the built-up energy becomes too great.