Photo By: Digital creation obviously, but I cannot locate who created this. If anyone knows please pass it on. I added some Fun Facts I think you may like at the bottom as well.

DON’T FORGET: The night of August 20 (tomorrow) and the morning of Aug 21 is a “Seasonal” Blue Moon! BUT what type of Blue Moon is it as there are 3 kinds?

Type 1: Two (2) Full Moons in a single calendar month are called “CALENDAR” Blue Moons and they occur on average every 2.7 years and these are the “modern” definition of the event. The last one was about a year ago, August 31, 2012 and the next few of this type will take place on:
July 31, 2015
January 31, 2018
March 31, 2018
October 31, 2020

Type 2: These are called “SEASONAL” but I like to call these your Grandfathers Blue Moon as they are the original definition of the event. Back in the day the standard was that a Blue Moon was any season that had 4 full moons….the 3rd of which was considered a Blue Moon. Seasons by calendar are defined as the time periods between SOLSTICES and EQUINOXES or vice versa. The last one was on November 21, 2010 and this is what we will be seeing tomorrow. After this week the next Blue Moon of this sort will fall on:
May 21, 2016
May 18, 2019
August 22, 2021

Type 3: The final type is an actual BLUE MOON…..but you’re going to need some tools. Preferably an active volcano, ash and an atmosphere to deploy it into. For years volcanic eruptions have been associated with blue colored moons. Why? most volcanic ash is about 1micron wide which just happens to be the length of a wavelength of red light. Thus, the red light is scattered and the blue shows through. Massive fires also have the ability to do this as well. Ever notice something looking bluish (Forest fires, grill smoke etc.) as you view it through smoke? There you go…..
I want to add a bit to the scattering of light. Ever notice when the Sun and Moon are low on the horizon they are pink, orange or even sometimes reddish? Well the opposite effect is in play with a TRUE Blue Moon. When objects are low on the horizon, say, 30deg or less you are looking through about 2x the atmosphere you will be seeing them through when they are overhead or near zenith. Atmosphere contains aerosols that are much smaller than 1 micron in diameter and those scatter BLUE light, letting the red show through. So don’t be surprised when your Blue Moon this week is more red with a transition to white than any other color, especially blue!

FUN FACTS: So we’ve covered Blue Moons and we know what Full Moons and New Moons are but have you ever heard of a “Dark Moon” or “Black Moon”?!
Though not as established as the Blue Moon in popular culture, a Dark Moon is typically when there are 2 New Moons in a calendar month (I like to call them OREO Moons…..get it, never mind). There will be two happening through the year 2015 and they happen on January 30, 2014 and March 30, 2014. So if you are an amateur astrophotographer these months will be GREAT!
A Dark Moon can also be when there is no full moon at all in a calendar month but there are none of those to come at least through 2015.
Interestingly enough, with the January & March Dark Moons that leaves little February with no New Moon at all. I don’t think there’s a fun term used to describe a calendar month with only 1 Full Moon and no New Moons or the opposite where once about every 18 years February is at it again but this time there will be no Full Moon and only 1 New Moon (February 2018)……hmm, anyone have any ideas?

ALSO: Keep in mind that none of this is actually relevant to our day to day lives, astronomy or anything else, it’s just orbital mechanics wrestling with our man-made calendar system. As far as popular culture, it’s like the “Super Moons”, just embrace it and enjoy seeing something unusual that also helps get the average person that doesn’t normally look up to do so.

Moon Giant Blue Moon Calendar:

Moon Connection page on Blue Moons:

Date and Time Blue Moon Page:

Image | This entry was posted in Astronomical Events, Astronomy (Learning), Astrophotography (Wide Field), Images, News, Solar System and tagged , , , , , , . Bookmark the permalink.

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