How To Find Out Your Moon Sign? Part 1: Using a Book
If you have a book like that, please do not trust it. The situation with the moon signs is a bit more complex than that. The Moon can change sign at any moment during a particular day, and so to find out in which sign it was at the moment of birth you need to take into account both the time of birth and the time zone of the location where the person was born.
Let's consider an example. I have a book by David Wells titled "Your Astrological Moon Sign. Werewolf, Angel, Vampire, Saint? Discover Your Hidden Inner Self". This book offers Moon Tables that were designed to help the reader to find out his or her Moon Sign. Let's have a look into those tables. Let's say you were born in 1975, on the 5th of May. For May 1975, we'll find in the tables the following records:
04 17:33 Pis
07 06:02 Ari
What this means is that the Moon entered the sign of Pisces on the 4th of May 1975 at 5:33pm and remained there until the 7th of May, 6:02am. Therefore, everyone who was born on the 5th or the 6th of May that year had Pisces for their Moon Sign, and not even the time of birth will be needed to figure that out. So simple.
But what if you were born on the 4th of May instead? Before the Moon entered Pisces on that day, it was in the previous sign, Aquarius. So, you might guess that if you were born before 5:33pm, your Moon Sign is Aquarius, after that — it's Pisces. Is that really so? Unfortunately, not. Before using the Moon Tables, you were supposed to check the very first page of them, which states: "The times shown here are GMT. If you were born outside the UK, please readjust your time of birth to GMT". In fact, even if you were born in the UK, life won't be that easy for you: you'll need to take into account the daylight saving time, and whether it was in use at the moment of your birth. 5:33pm GMT on the 4th of May will be actually 6:33pm GMD.
And if you were born in New York, the time of the Moon's entry into Pisces was 12:33pm EST. Again, you'd need to figure out whether the daylight saving time was in use, and if it was, you should use 1:33pm EDT instead. For other locations, like Los Angeles, Tokyo, Sydney, all the times will be very different, of course.
Even that isn't complex enough to be precise. In some locations, the time zone rules changed over time. For example, if you were born in Florida relatively recently, you could use Eastern Time for your time zone in the same way you'd do that for New York. However, a little bit further into the past (probably in the 1940s, but that's from the top of my head) Florida didn't observe daylight saving time, and you should take that into account if it's relevant for your date and place of birth.
To summarise, it is possible to use a table like in David Wells' book to find out your Moon Sign. If you were born on one of those days when the Moon stayed within the same sign for the whole day, you'll get the answer quickly and easily (although if your time zone was different from GMT, you'd have to make an adjustment to figure out where the day begins and ends). However, if you were born on one of those days when the Moon changed its sign, you'd need to take into account the time zone of birth, the daylight saving time, and to do a bit of calculation before you'll be able to figure out your Moon Sign.
If your book tells you that you can find out your Moon Sign simply from the date of birth, don't trust that book.
By the way, did you know that I've written a Moon Sign book myself? It doesn't contain any tables as it relies on very different ways of finding out your Moon Sign. I will discuss one of those other ways in the next post.