First of all, both the numbers 12 and 13 are sacred numbers in general and especially when considering the Moon. The whole idea that 13 is better than the so-called patriarchal number 12 has grown out of a misunderstanding about the importance of both numbers.

The Moon literally connects with the number 12 – in its synodic cycle and it connects with 13 – in its sidereal cycle. See end of this article for more.

There have never been 13 Signs because Signs are Seasonal…

Astronomers and Astrologers are often confused by the difference between Signs (that are seasonal or where the Sun rises at Solstice, Equinoxes and the days inbetween) and constellations representing the starry backdrop the seasons move through. The problem is both the seasons and signs were named the same names, when the difference between them was forgotten, and that has contributed to all the confusion.

NOTE: Finally an astronomer writes about the Difference between Signs and Constellations in this Article on EarthSky.org

Signs and Constellations are two completely different things.
This can not be said enough as we are now remembering the difference between Signs and Constellations. So again to support this understanding, it helps to understanding the signs are seasonal connected to Solstices and Equinoxes and the constellations are the star patterns the seasons or signs move through. That means over time the constellation the December Solstice Sun (0 Capricorn – representing the longest night and shortest day in the Northern Hemisphere and the opposite in the Southern Hemisphere) rises in a different constellation about every 2160 years. Every 26,000 years it comes back to a starting point hanging out at that point for at least 72 years.

This precessional movement is very slow moving a seasonal point through the back drop of the stars one degree in 72 years, taking nearly 26,000 years to make one complete circuit. This means over 26,000 years every season is with every star group along the ecliptic. However, in our current time with the seasons having the same names as the constellations both astronomers and astrologers get confused.

That is why in the Shamanic Astrology paradigm we use the alternate name for the constellations as listed further below.

In the list below are the dates the Sun is in its Seasonal Signs and another table for when the Sun is traveling through different Constellations. Be sure to note the difference in the dates as that describes the precessional cycle from the time humanity forgot there was a difference between signs or seasons and constellations. This 15 minute YouTube is mini-teaching on this issue that helps to explain the difference with visuals. (This YouTube is also posted below)

Plus, this article also explains this difference in greater detail http://shamanicastrology.com/articles/the-difference-between-signs-and-constellations

I have included an Article that appeared in early 2011 about the 13th Sign with comments from me in parathensis and/or bolded or italics to help in understanding what is really happening.

Article: Your (So Called) “Real Sign”

Note: This Title and article is based on constellations not signs (or the seasons) and is also based on the astronomers redrawing of the constellational boundaries that happened in 1922 as described in this article here note this page is slow to load taking you to the main page in the article Titled: The New International Symbols for the Constellations Author: Russell, H. N. Published in the Journal Popular Astronomy, Vol. 30, p.469 Bibliographic Code: 1922PA…..30..469R – it was published in October 1922

Additional Note: the actual article is posted in blue

The table below lists the dates when the Sun is actually within the astronomical constellations of the Zodiac, according to modern constellation boundaries and corrected for precession (these dates can vary a day from year to year).

You will most likely find that once precession is taken into account, your zodiac sign is different.

(Note: the above statement is incomplete coming from the misunderstanding about the signs or seasons having the same name as the constellations but the seasons are not the same as the constellations or star patterns. The seasons relate to Winter, Spring, Summer and Fall. This fact is not being considered in this article rather it is only looking at the constellational star patterns. Interestingly the one things astronomers and tropical astrologers agree on is that Zero degrees of Capricorn, Aries, Cancer and Libra mark the Solstices and Equinoxes – seasonal points we experience every year.)

And if you were born between November 29 and December 17, your sign is actually one you never saw in the newspaper: you are an Ophiuchus! The ecliptic passes through the constellation of Ophiuchus after Scorpius.

(Note: the reason the Sun passes through Ophiuchus is because the boundaries of the constellations were redrawn as mentioned above. Before the constellations were redrawn in the 1920’s Ophiuchus was NOT part of the zodiacal constellations. Plus Ophiuchus is a constellation NOT a seasonal sign so from the Tropical system (or seasonally based signs) Ophiuchus doesn’t figure in because its not one of the 12 seasonal signs determined by the Solstices and Equinoxes. See the listing below)

Check out your “real” zodiac sign below and see what the sky looked like on your birthday by going to the Birthday Sky application.

(Note: I have included the tropical signs and the dates the Sun is moving through them based on our seasonal experience along with the alternate name of the constellation. So for example if you were born on March 1 the Sun was in the constellation of the Waterbearer and it was in the seasonal sign of Pisces, or if you were born on March 21 when the Sun was at Zero Aries marking the Spring Equinox the Sun was located in the constellation of the Fish and the sign of Aries or Spring).

The Table Below is from the article with some adjustments. The first bolded sign name is what the article listed with the dates the Sun is in that constellation. I have given the alternate constellation names and dates the Sun is in the seasonal or tropical sign. Below the article’s listing I have included two more tables that separate the listings as another way to show the difference.

Capricornus/Goatfish – The Sun travels through this constellation Jan 21 to Feb 16 and this is the constellation also known as the Goatfish. The Sun is in the seasonal  sign of Capricorn December 21 to January 20. From the tropical sign based system calibrated from a seasonal perspective the sign Capricorn starts with the Winter Solstice (or December Solstice) when the Sun reaches the coordinate that marks the longest night and shortest day.

If we call the constellation by its alternate name, the GoatFish, then the Sun is in the Goatfish from Jan 20 to Feb 16 but it is in the seasonal sign of Capricorn marked by the Winter Solstice…usually on Dec 21…for the next 30 days.

Aquarius/Waterbearer – The Sun travels through this constellation Feb 17 to Mar 11 This is the constellation also known as the Waterbearer. The sign or season of Aquarius begins 30 days after the December Solstice and  is from January 19 or 20 to February 18 but the Sun travels through the Waterbearer Feb 16 to Mar 11.

Pisces/Fish – The Sun travels through this constellation March 12 to Apr 18 This is the constellation also known as the Fish. The sign or season of Pisces begins 60 days after the December Solstice and is from February 21 to March 20 when the Sun reaches the Spring Equinox point of Zero Aries

Aries/Ram – The Sun travels through this constellation Apr 19 to May 13  This is the constellations also known as the Ram. The sign or season of Aries occurs when the Sun reaches a balance of equal day and night usually around March 19 or 20 and is in the season of Aries until April 19 or 20.

Taurus/Bull – The Sun travels through this constellation May 14 to Jun 21 This is the constellation also known as the Bull. The sign or season of Taurus starts 30 days after the Spring Equinox around April 19 or 20 to May 20 or 21

Gemini/Twins – The Sun travels through this constellation Jun 22 to Jul 20 This is the constellation also know as the Twins. The sign or season of Gemini begins 60 days after the Spring Equinox on May 20 or 21 to June 20 or 21

Cancer/Crab – The Sun travels through this constellation Jul 21 to Aug 10 This is the constellation also known as the Crab. The sign or season of Cancer begins on the day of the June Solstice when the day is longest and lasts for 30 days from June 21 to July 22

Leo/Lion – The Sun travels through this constellation Aug 10 or 11 to Sep 15 or 16 This is the constellation also known as the Lion. The sign or season of Leo begins 30 days after the June Solstice on July 22 (until 2040) to August 22 as the days are beginning to shorten.

Virgo/Virgin Priestess – The Sun travels through this constellation Sep 17 to Oct 30 This is the constellation of the Virgin Priestess. The sign or season of Virgo begins 60 days after the June Solstice on August 22 to September 22

Libra/Scales – The Sun travels through this constellation Nov 1 to Nov 23 This is the constellation also known as the Scales. The sign or season of Libra begins when the Sun reaches the balance point of equal day and night on September 22 and lasts for 30 days until October 22.

Scorpius/Scorpion – The Sun travels through this constellation Nov 24 to Dec 21. This is the constellation of the Scorpion. The sign or season of Scorpio begins 30 days after the Autumnal Equinox on October 22 and lasts for 30 days until  November 21

Ophiuchus/Serpent Bearer – The Sun travels below this constellation (not through it) Nov 29 to Dec 17 This constellation only has a foot on the ecliptic and that only happened in 1922 when astronomers redrew the constellational boundaries bringing the feet of the Serpent Bearer down to the ecliptic. However, this constellation is more accurately placed along the Celestial Equator way above the ecliptic or path of the Sun.

Sagittarius/Archer – The Sun travels through this constellation Dec 22 to Jan 20 This is the constellation also known as the Archer. The sign or season of Sagittarius begins 60 days after the Autumnal Equniox on November 21 and lasts 30 days until the December Solstice usually on December 21.

Final Note: Hopefully this gives a sense of the difference between the constellations and the signs. The intent is to sort out the confusion that occurs because the signs and constellations have the same names. If we use the alternate names for the constellations as listed below it helps to have a sense of the difference between the tropical signs and the sidereal zodiac.

Again, highly recommended is viewing this YouTube (also posted at the end of this article) explaining with visual images the seasonal signs and how they move through the constellations one degree every 72 years. It is this slow movement of the seasonal signs through the constellations that was forgotten and when that happened the seasons wound up being considered the same as the constellations with the same names. Unfortunately, the confusion continues to this day and that is why Shamanic Astrology (following the lead of Rudoph Steiner) uses the alternate name for the constellations as a way to keep them separate by using a different designation because they are entirely two different things.

Here is the list when the Sun is traveling through the Constellations 

The constellation Capricorn a.k.a The Goatfish – Jan 21 to Feb 16
The constellation Aquarius a.k.a. The Waterbearer- Feb 17 to Mar 11
The constellation Pisces a.k.a. The Fish – Mar 12 to Apr 18
The constellation Aries a.k.a. The Ram – Apr 19 to May 13
The constellation Taurus a.k.a. The Bull – May 14 to Jun 21
The constellation Gemini a.k.a. The Twins – Jun 22 to Jul 20
The constellation Cancer a.k.a. The Crab – Jul 21 to Aug 10
The constellation Leo a.k.a. The Lion – Aug 10 or 11 to Sep 15 or 16
The constellation Virgo a.k.a. The Virgin Priestess – Sep 17 to Oct 30
The constellation Libra a.k.a. The Scales – Nov 01 to Nov 23
The constellation Scorpius a.k.a. The Scorpion – Nov 24 to Dec 21
The constellation Sagittarius a.k.a The Archer – Dec 22 to Jan 20

And because in 1922 the boundaries lines defining the constellations were redrawn to include the foot of Ophiuchus on the Ecliptic, I have included the time astronomers claim the Sun is passing through this constellation below.

The constellation Ophiuchus a.k.a The Serpent Bearer – Nov 29 to Dec 17 (However, the Sun is also still in the body of the Scorpion during this time.) See personal story with Serpent Bearer

When the Sun is traveling through these seasons (not constellations or star patterns)
Note: dates may vary a day or so on either side and tend to drift over time. Another variation is based on what time zone you are in at the time as the Sun enters the seasonal sign.

Capricorn (December Solstice) December 21 – January 20
Aquarius (First Cross-Quarter) January 19 or 20 – February 18 or 19
Pisces (Right before March Equinox) February 19 or 19- March 19 or 20
Aries (March Equinox) March 19 or 20 – April 19 or 20
Taurus (Second Cross-Quarter) April 19 or 20 – May 20
Gemini (Right before June Solstice)  May 20 – June 20 or 21
Cancer (June Solstice) June 2o or 21 – July 21 or 22
Leo (3rd Cross-Quarter)  July 21 or 22 – August 22 or 23
Virgo (Right before the September Equinox) August 22 or 23 – September 22
Libra (The September Equinox) September 22 – October 22 or 23
Scorpio (The 4th Cross-Quarter) October 22 or 23 – November 21 or 22
Sagittarius (Right before the December Solstice) Nov 21 or 22 to Dec 21

Is 12 or 13 the Most Sacred Number of the Moon?

In recent years, there have been many articles and books claiming that the number 13 is the most sacred number for the Moon. However, the Moon actually intimately connects with the numbers 12, 13 and 19.

If you are tracking the Moon return to a certain zodiacal degree, say zero Capricorn, it will return to that degree every 27.3 days. If you divide 27.3 into 365 days in a year – the closest whole number is 13. That means the Moon will cross that point or any other starting point 13 times each year.

If you are tracking the Moon phases from Full Moon to Full Moon or any other phase (i.e. New Moon to New Moon or First Quarter Moon to First Quarter Moon) it returns every 29.5 days. If you divide 29.5 into 365 the closest whole number is 12. That is why there are 12 months (moonths) in a year.

It is important to realize the number 13 for the Moon is NOT what most people think it is. There are NOT 13 Full Moons every year regardless of whether you are tracking a calendar year, or a seasonal year – from one December Solstice to the next. Actually more often than not there are only 12 Full Moons a year. That is why both 12 and 13 are sacred numbers, or sacred patterns for the Moon.

Additionally, the 19 year pattern or cycle of the Moon is significant to our personal experience especially when we are turning 19, 38, 57, 76, and 95. This 19 year Moon cycle is related to Nodes of the Moon and the Eclipses. The point here is that there is more than one sacred number for the Moon, as the Moon has many patterns that are worth knowing and understanding, because these patterns do play out in our personal and collective experience. From this article https://cayelincastell.com/the-moon-and-blue-moons/