Ephemeris – Foundation of the Horoscope

The ephemeris lists the daily positions of the Sun, the Moon, and all the planets in the solar system, as they move through the signs of the zodiac. The ephemeris, in fact, serves as the foundation of the horoscope. It is used by astrologers as a handy look up table to quickly suss out the positions of the planets for any of interest. (By the way, when I say “planets” from here on out, I also include the Sun and Moon for convenience, as do all astrologers.)

Say you know someone who was born on March 15, 2001, and you want to quickly find out the planetary sign positions in their horoscope. (If you have only learned about Sun signs, just a quick note that the Moon, and other planets, are also to be found in various zodiac signs because we map the entire solar system in the horoscope.) Here is the ephemeris for the daily positions in the month of March 2001:

This ephemeris has been generated by an astrology software application that I have built for my own work. I call it Lifespan, and I will be using it extensively in these sessions for various illustrations.

The first column in the ephemeris lists the days in the month of March 2001. The subsequent columns, Sun through Pluto, list the zodiac sign positions of the respective planets for each day. The last column, labeled NNo, is for what’s called the North Node. It’s not a planet, but a point in the horoscope, to which we will get later, when we do a deep dive into the full horoscope chart.

At the top right above the table you see the header Tropical Daily Ephemeris at UT 00:00 – I will elaborate on “Tropical” in just a bit, and get into UT 00:00 in Take 2 of the Ephemeris discussion.

Right now, let’s unpack the value in each cell of the ephemeris.

Degree and Minute Position

Let’s take a look at March 15, which is our target of interest.

For instance, in the cell for the Sun position in the 3/15 row, it says 24Pi28. What does this mean? To better understand this for all the planet positions, I am going to detail them for 3/15 in the following expanded table:

Moo(n)Sg (Sagittarius)0303
SunPi (Pisces)2428
Mer(cury)Aq (Aquarius)2719
Ven(us)Ar (Aries)1701
Mar(s)Sg (Sagittarius)1344
Jup(iter)Ge (Gemini)0454
Sat(urn)Ta (Taurus)2612
Ura(nus)Aq (Aquarius)2241
Nep(tune)Aq (Aquarius)0755
Plu(to)Sg (Sagittarius)1516
N(orth)N(ode)Cn (Cancer)1149

What do the degree and minute values mean? Each zodiac sign covers 30 degrees of arc. So all 12 signs put together cover the entire 360 degree sweep of the sky. (The astronomical reality is somewhat different, the constellations don’t have these regular equal-length boundaries, but astrology works with a modified view.) Here’s a simple visual to go with this idea:

So if the Sun is listed at 24 degrees and 19 minutes of Pisces, it means that the Sun has traveled through 23 degrees and 19 minutes of arc of the total 30 degrees in Pisces. Another 6 degrees and 41 minutes, and the Sun would finish the entire 30 degrees span of Pisces, and would just about be entering the next sign, of Aries. The exact degree/minute position, while not necessary to know the sign of a planet, is absolutely critical for determining aspects, and for forecasting work, as we will see in later sessions.

In the ephemeris, Lifespan color codes the sign according to element: red for fire, blue for water, gray for air, and green for earth. This makes it easy, at a glance, to assess the spread of elements in a horoscope. So for someone born on March 15, 2001, there are 4 planets in fire (Moon, Venus, Mars, and Pluto), 1 in water (Sun), 4 in air (Mercury, Jupiter, Uranus, and Neptune), and 1 in earth (Saturn). The element-spread is one of the factors that is considered when interpreting the horoscope.

Tropical Zodiac

Returning to the “Tropical” in the header above the table, what you have here are the “tropical zodiac” placements for the planets. Tropical astrology is the primary system of astrology used in the western world. In tropical astrology the sign positions don’t correspond to what we actually see in the sky.

For instance, at the spring equinox in March, tropical astrology places the Sun at 0 Aries. But in reality, were you to see where the Sun is in the sky, you would find it the constellation of PISCES. This dissonance happens because Tropical astrology is based on our experience of the seasons, and the spring season starts at the spring equinox. Which is permanently tied to zero degree of Aries.

Likewise the summer solstice in June is tied to zero of Cancer, the autumn equinox in September to zero degrees of Libra, and the winter solstice in December to zero of Capricorn. 

One could say that western tropical astrology is therefore experience-oriented, as in how you experience and react to circumstance. After all, two people facing the same circumstance may feel and react to it in very different ways, and thereby experience life differently.

Tropical astrology is predominantly used in the western world, while Vedic or Indian astrology uses what’s called the Sidereal zodiac. In this system, the same 12 zodiac signs are seen relative to the positions of the fixed stars, not the seasons, and therefore correspond much more closely to the actual astronomical positions as seen by the eye.

There is a way to compute the sidereal positions off of the tropical positions. We won’t get into every single detail here, but in short, you can get the sidereal position for a planet by subtracting roughly 23 degrees from the tropical position. This might well move a planet to the previous sign! In the March 15, 2001 example above, the sidereal positions of all the planets that are less than 23 degrees into their sign will move to the previous sign. So, for instance, Moon’s sidereal position will move to Scorpio, the sign before Sagittarius. Venus will move to Pisces (before Aries), Mars will move to Scorpio, etc.

Getting an Ephemeris, and Glyphs for Signs and Planets

Finally, you can access the ephemeris for any year in a 2000 year period at astro.com. (See the Horoscopes page for details.) Below is a screenshot of the ephemeris for March 2001:

Astrodienst is the company that produces the ephemeris, also for UT 00:00 of any month and year. You can compare the positions between these and the Lifespan ephemeris and see they are pretty much the same. For the signs, their symbols are used instead of their names.

Here is a roundup of the symbols for the signs, in no particular order of signs, as well as the symbols for the planets, in no particular order. All the symbols that appear here have been generated by Lifespan.

The symbol is called a glyph in astrological parlance. The second to last column in the Astrodienst ephemeris is not for a planet, and is not typically used by astrologers. The third to last column is for what is called the “mean node”, which is a variant of the north node – again, not something that is used by astrologers. The second column is a sidereal quantity that can be ignored.

As for the deal with UT 00:00, that’s a whole other story we will get into in Ephemeris – Universal Time.


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