Blue moon is `traditionally’ the second full moon in the same calendar month! What’s an astro Blue moon? Well, that is what I consider to be a true blue moon! It happens when there are two consecutive full moons in the same astrological (sun) sign!
I give this more importance, because Calendar months are too arbitary. Depending on when you start to count the dates, a calendar month can vary. Indeed most religions of the world have their own calendars. Even the modern western calendar has been chopped, changed, dates added, reduced and adjusted by various Kings/ Emperors of the past (Julian calendar, Gregorian calendar and so on).
Data
We are about to have 2 full moons in the same sign!
- Full Moon on 22nd July 2013 – at 0’06” Aquarius.
- Full moon on 21st August 2013 – at 28’11” Aquarius.
So you see, 2 consecutive full moons in the sign of Aquarius ..! By this approach, the 2nd full moon – 21st August’13 – is an Astro-BlueMoon!
Magical
This has more magical significance.. because a) people of that Zodiac sign get 2 full moons in one year (normally we all get one full moon in our own signs). People not of that particular zodiac sign van also take a big advantage of this astro-opportunity! For example, if you like to do some magic that relates to a certain aquarius quality, or want to work magically on the `house’ where this sign encompasses, you get 2 opportunities.
You can either do the same magical work twice…or start magical work on the first full moon of this sequence, and conclude it at the 2nd one.
Note: to make use of this magically, you must start the magical or esoteric work on 22nd July’13, and conclude/ repeat it a month later on 21st August’13.
Good luck!
–Mani Navasothy (astro-mage!)
Links / more
QuantumPhoenix 
Hey Mani,
Some interesting views on a blue moon in Aquairus. I can’t say I’m completely with you but nice to see you putting your ideas out there!
Dayita
Thank you Dayita. Nice to connect with fellow astrologer. Bright Blessings. 🙂