There are many astrological terms
found in the historical record. Many are clear enough in
themselves to understand. There also appears to have
been some that the earlier astrologers each had their
own terms for which caused both confusion and some
rather bitter accusations among them. The term *transit*
for example is one such word. In our understanding today
we take it to mean any time one planet passes another in
degrees of longitude on the ecliptic. However, the
astrological historian Al Biruni, goes into great detail
in his treatise called “Al-Biruni on Transits”
where he clarifies the misuse of terms and sets the
record straight so to speak.
There is another term much used today
that I find has been misunderstood both by astrologers
today as well as some in ancient times. This is the term
*orb of influence*.
We won’t find this expression in
early Hellenistic astrology. When and where it was
conceived and who coined the expression is lost to us.
There is a trace of it discussed in the collection of
material that is attributed to Hermetic teaching called
the “Liber Hermetis”. However, there is some
difference of opinions as to when this material was
compiled and if it is genuinely “Hermetic”. There are
those who attribute this to pre-Arabic era (6th
and 7th century AD), while other historians
will point to a post Arabic Era (ca 1100 AD) compiler.
This particular term and consideration found in this
material, does cast some doubt about this material being
Hermetic and deriving from pre-Arabic teachings!
In a chapter where the compiler is
discussing how to make predictions concerning the
parents from the lunar phases, we find the forerunner of
the teaching on orbs. The compiler writes,
«...because the perimeter of the same Moon is 20 degrees
and its distance [to the Lot of the father] is five
degrees, we say that the Moon aspects the part. It is
contained by half a perimeter which is according to a
conjunction which is 10 degrees...»
Now nowhere in this text does the compiler refer to this
as an orb! He merely says perimeter. Nonetheless, the
editor of this translation footnotes the word
perimeter and writes,
«Orb is a
fairly decent translation of the original Greek word `perimetros'
from which comes our word perimeter. Also, we have to
keep in mind that for most modern astrologers an orb is
actually one half of what the renaissance and medieval
astrologers would have considered an orb. Ours is the
radius of the circle or orb surrounding the planet,
theirs was the diameter.»
question that arises in my mind is; is the assertion
that *orb* is a decent translation of *perimeter* valid?
As an engineer and mathematician, I’d say absolutely no,
because we can describe the perimeter of a square as the
length of its side, or the perimeter of a triangle as
the length of a right side to the apex. The perimeter of
a circle is its diameter. Perimeter also means the
distance around an object, such as the perimeter of a
square or triangle. Perimeter does not automatically mean orb nor is it
necessarily synonymous. The original authors of these
texts were both mathematicians and astronomers and it is
impossible for me to believe that they were referring to
perimeter in such a context as orb.
“Liber Hermetis”, the author only says
that the entire “perimeter of influence” of the
Moon is 20°
and that half of that perimeter is 10°.
author is speaking of the perimeter which is the outer
boundaries measured as its total length. (figure 1)
The *perimeter* in the context of an orb or circle then,
is the diameter of that orb or circle. In figure 1, the
perimeter of the Moon’s orb as pictured is 24°,
half of its perimeter (called its radius) extending
before it and half behind. The difference in my figure
and the example in the Liber Hermetis is that the author
there uses a diameter of 20°,
“the perimeter of the same Moon is 20 degrees”
where half of that *perimeter* extends before the Moon
and the other half behind, “It is contained by half a
is no doubt about what the author is describing yet
there is also no reason to assume he is talking about an
orb or circle. The fact of the matter is he could just
as easily been describing something entirely different.
if, for example, each planet has two orbs, one orb
before it and one after? The planet’s *perimeter*, in
that case, would extend from the extreme of the one orb
before to the extreme of the orb after. (figure 2)
perhaps, to our “Newtonian” thinking, that sounds
strange. The authors of these ancient texts however were
not, “Newtonian”. Their conception of astrological
influence was “quantum” in its conception. How did they
conceive this perimeter? Was it a perimeter surrounding
the planet as we conceive an *orb*?
what we “perceive” may in fact be an orb with a
source at the middle such as is most often used as an
example of a planet’s orb. But is what we “see” an
accurate description of what it is?
Thanks to modern techniques we are at last able to
photograph what a planets *orb* actually looks like,
like this very recent photo (figure 3) of a stars’
Does it look uncannily like my suggestion referring to
two orbs emanating before and behind?
about a planet’s *orb of Influence*? Look at a photo of
the earth’s field of *influence*. (Figure 4) Can you see
its “Orbs of influence” before and behind?
Orbs of Influence in the Historical
and put some clarity on what is asserted in the record by
investigating just what the ancients do say and what they do
Ma’shar (c.787-886) writes of the planets’ influence.
« Each one
of them [the planets] in its body has power over a certain
number of degrees before and after it.  The power of the
body of the Sun is 15 degrees in front of it, and the
same number behind it. The power of the body of Saturn
and Jupiter, both of them, is nine degrees in front and
behind them both. The power of the body of Mars is eight
degrees in front and behind it. The power of the body
of Venus and Mercury, both of them, is seven degrees in
front and behind them both.»
Abu Ma’shar’s use of words here is very important! He does
not say they have an orb of light that reaches out before
and behind but he carefully says, “…has power over
a certain number of degrees before and after it.”
not say what that “power” is or even tries to describe it.
He only specifies that each has power over a certain number
of degrees “…in front of it, and the same number behind
This is not much different than the description in the
“Liber Hermetis”, which also only refers to a
*perimeter* that extends before the Moon and behind it.
the perimeter of the same Moon is 20 degrees and its
distance [to the Lot] is five degrees, we say that the Moon
aspects the part. It is contained by half a perimeter which
is according to a conjunction which is 10 degrees...»
In Abu Ma’shar’s assertion the «perimeter» of the Sun is 30°;
i.e. its diameter! The «perimeter» of the Moon is 24°,
Sahl ibn Bishr (1st half of the
9th cent.) otherwise known as Zahel wrote in his
“Introduction to Astrology",
know that the orb of light of the Sun is 30 degrees, the
half of which is in front of him, i.e. fifteen degrees in
front of the Sun itself and fifteen degrees behind.
Whenever the degrees, between the Sun and any planet, are
from 1° up to 15°, then it [the Sun] casts its light over it
[the planet] and is being joined to it. And the light of the
Moon is twelve degrees in front and twelve behind.
And the light of Venus and Mercury, of each one of them,
seven degrees in front and seven behind these [lacuna
3-4 words]… join to planet the light of Saturn and Jupiter,
of each one of them, nine degrees in front and nine
behind. Also, the light of Mars is eight degrees in
front and eight behind.»
The difference between Zahel and Abu Ma’shar is NOT what
they consider the perimeter (for those are the same), but it
is the language describing the same conceptualisation. In
Zahel’s case, he literally calls it an “orb of light”.
continues this teaching of the planet’s influence in front
and the same behind, writing;
Saturn] the influence of his body is 9 degrees before
and also after him.
Jupiter] …and the orb of influence of his body is 9 degrees
before and after.
Mars] …and the orb of influence of his body is 8 degrees
before and after.
the Sun] …and the orb of influence of its body is 15 degrees
before and after.
Venus] …The orb of influence of her body is 7 degrees
before and after.
Mercury] …and the influence of his body is 7 degrees
before and after.
the Moon] …and the influence of her body is 12 degrees
before and after.»
Now if there are any who would like to assert that Ibn Ezra
means that these degrees are the total orb before and
after, i.e. half of these degrees he gives for each planet
before and the other half behind, that misconception can be
set straight by reading the sample he gives of a
«An example is
when the distance between the Moon and Saturn is 8 degrees,
before or after, then each one of them is within the [orb
of] influence of the other. But when there are 10 degrees
between them, then Saturn is within the influence of the
Moon, but the Moon is not within the influence of Saturn.»
The Moon's orb of influence is 12 degrees, so when she is 10
degrees from Saturn he is within her orb of influence [in
front of her as she is applying], but Saturn's orb of
influence is 9 degrees so the Moon does not fall within his
orb which is 9 degrees behind him because she is applying to
him. (Figure 5)
are 8 degrees apart then both fall within the orb of
influence of each other.
The Planets are Conjunct
Ezra means exactly what he says; the planets orb is the same
number of degrees he has listed both before and the same
The language used by Ibn Ezra is also interesting for he
says, the influence of their body is so many degrees before
and after (like Abu Ma’shar) yet he also calls that
influence an orb before and after. In other words, the
influence of the planets body is an orb of influence before
it and an orb of influence behind it.
get to Bonatti, he says nothing contrary to this teaching.
Of Saturn and Jupiter, he simply writes,
quantity of his orb is nine degrees.»
And of Mars, he says similarly,
quantity of his orb is 8 degrees.»
In these first three, he seems to be echoing Alchabitius in
his language. When he gets to the Sun, that changes as he
quantity of his orb is 15 degrees before and after.»
In the middle of these planets he suddenly echoes the others
by specifying, «...before and after». In fact, he
goes on in the next sentence to say,
understand this concerning every orb of the planets, namely,
[that it is] before and after.»
Now again there are those who would like to assert that what
Bonatti meant by degrees before and after is that
those are the total degrees both before and after....for the
Sun, 15 degrees total, before and after, so that its moiety
(or half) is 7.5 degrees before it! Well, I do know that is
NOT what Bonatti meant by before and after also, for
when he gets to Venus he is most clear when he states,
of her orb is 7 degrees before and just as many after.»
Bonatti does not vary one tiny nanometre from the teaching
of the ancients as concerning the influence of a planet. In
harmony with Abu Ma’shar, he also states that every orb is
before and after, which leads us back to my suggestion that
we are talking about two orbs for each planet; one before it
and one after.
of the main stream traditional authors, I surprisingly found
support for this suggestion in the one astrologer I least
expected to find support from, namely William Lilly. I am
going to quote this section in Lilly’s first book of his
«…I will again
insert the Table of the quality of their Orbs, although I
have in the Planets several descriptions mentioned them;
they stand that as I have found by the best Authors and my
What is important in this sentence from Lilly is that he is
referring the reader back to what he has previously written
concerning the quality of their orbs, «I have in the
Planets several descriptions mentioned them». He is
re-affirming what he has written concerning them and is
suggesting what they should be according to his experience
and lists two columns as reproduced below. The first column
of degrees is what Lilly says according to his experience.
The second column of degrees is what he refers to the
ancients and he lists in his “Description of the Planets”.