August Night Sky

The Full Moon appearing this evening is named after North America's largest fish - the sturgeon. Other names for this Full Moon include Green Corn Moon, Grain Moon, Barley Moon and Fruit Moon.  There is a great deal to digest about the moon this month as this full moon is a whopper.

The Sturgeon Moon has its origins in the great number of sturgeon that were once found in the lakes and rivers in North America.  It’s likely that with the arrival of European settlement the name was borrowed from native-American usage.  I live close to Sturgeon Bay - named for the large number of sturgeon found here when settlers arrived.  Nowadays, over-fishing has just about eliminated this species from the Great Lakes.  Sigh.  The largest population of sturgeon in the world can be found in the Lake Winnebago waterway system not too far away.

August's full moon is special.  Not only does it coincide with the Perseid meteor shower it also happens to be a Super Moon, a Blue Moon and will pass very close to Saturn! 

A Super Moon results when a full moon reaches 90% of perigee - or closest approach to earth.  Consequently, it should appear 30% brighter and 14% larger than a moon at its farthest point (apogee).  This is the first of four Super Moons for 2024 - three more are scheduled for September 17, October 17 and November 15.

If the moon looks larger when it is nearer to the horizon that is known as moon illusion.  A trick of perception that has nothing to do with astronomy.  This illusion occurs because of how our brain interprets distance and size.  When the moon is just above the horizon we see it alongside trees, buildings and other objects, making it appear larger.  When the moon is high in the sky overhead there's nothing to compare it to, so it looks smaller.  This is all about how our brain works.

There are two types of Blue Moon and neither has anything to do with color.  Ordinarily a Blue Moon is a second full moon that appears in a calendar month. The 1937 edition of the now defunct Maine Farmers' Almanac (not to be confused with The Old Farmers Almanac) explained in their calendar that a Blue Moon occurs when one of the four seasons contains four full moons instead of the usual three.  The August 21, 1937 moon was the third of four full moons that summer when for no apparent reason it was reported as a Blue Moon..  Ever since, a seasonal blue moon refers to the third full moon in a season that has four full moons.

In many parts of the world the August Full Moon will occult the planet Saturn. While not the same as an eclipse, an occultation (word of the day) occurs when one celestial object passes in front of another temporarily obscuring the latter.  In our part of North America observers will see the moon make a pass very close to Saturn rather than an occultation around 10 PM on August 20.

Finally, the Democratic Party kicks-off their convention today - yes, coinciding with a full moon - so the party should be a doozy.

I told you this was going to be a whopper.

Fingers-crossed for good viewing conditions tonight and tomorrow.