Noel Tyl, Geocentric Latitude and the Celestial Sphere

On March 19th, I watched a discussion of the Vedic birth chart of Noel Tyl, presented by Kepler College in honor of Astrology Day. The sidereal Ascendant given was 07 Gemini 04′ (Lahiri ayanamsa), which at quick glance would mean that Tyl was born with his Ascendant degree at the very end of Gemini or the very beginning in the tropical zodiac. Looking up his birth data on astro.com, I found the following:

Noel Tyl’s birth data from astro.com

Sure enough, Tyl’s natal Ascendant for the birth time, which he recalled from memory, fell at 00 Cancer 04′, so that if he were born roughly 15 seconds earlier (around 3:56:45 pm), he would have had a Gemini Ascendant. Having chatted with Noel at several conferences and attended his lectures and workshops, I could see how a Gemini Ascendant could easily fit his personality and behavior style. In the Vedic chart, there is no question that Tyl’s Ascendant lies in Gemini. However, I believe that Noel used Cancer as his Ascendant in his own work with his chart.

There is yet another twist to the story. Noel, like many astrologers, calculated his Ascendant on the basis of the geodetic or geographical latitude of his birthplace. My own preference is to use the geocentric (planetocentric) latitude, because it is measured in the same coordinate system which we use to locate the stars and planets in the heavens. My math teachers always taught that we should not mix coordinate systems, often admonishing “don’t mix apples with oranges.”

A notable example of the problems caused by mixing measurement systems is the loss of NASA’s Mars orbiter, as reported by CNN in September of 1999: “NASA lost a $125 million Mars orbiter because a Lockheed Martin engineering team used English units of measurement while the agency’s team used the more conventional metric system for a key spacecraft operation, according to a review finding released Thursday.”

What, you may ask, is the difference between geodetic and geocentric latitude, and why does it matter? The Earth is not a perfect sphere. Instead, our planet is spheroidal and bulges a bit around its middle as it spins on its axis. On the other hand, astrological measurements are based on a model of the Celestial Sphere, which is a perfect sphere whose center is the center of the Earth. The following diagram from https://proj.org/operations/conversions/geoc.html should make this clear:

Geocentric (planetocentric) versus geodetic (geographical) latitude

You can see in the above diagram that geocentric (planetocentric) latitude projects the place of birth onto the Celestial Sphere from its center at the center of the Earth. The geodetic (geographical) latitude, in contrast, ignores the center of the Earth and instead projects the birthplace onto the Celestial Sphere on the basis of a perpendicular to the tangent to the birthplace on the Earth’s spheroidal surface. Thus, the use of the geodetic latitude in chart calculations mixes two distinct coordinate systems — tantamount to confusing apples with oranges and expecting to get a valid result. We measure the positions of the stars, planets, asteroids and the zodiac itself on the idealized Celestial Sphere with reference to the center of the Earth, but we abandon the Earth’s center when we calculate our personal Ascendants. Does this make sense, or does it introduce errors into our astrological reasoning?

Fore example, if we calculate Noel Tyl’s Ascendant using the geocentric latitude of his birthplace (the same system by which we measure the planets, stars and zodiac signs), we find that his Ascendant at 3:57 pm falls at 29 Gemini 54′ rather than 00 Cancer 04′. In other words, in the geocentric model of the universe, which is fundamental to Western astrology, Noel Tyl has a Gemini Ascendant for the birth time of 3:57 PM, and his chart with Placidus houses looks like this:

Noel Tyl’s birth chart calculated with geocentric latitude

We can test the Gemini Ascendant with a well-timed event from Tyl’s life. For example, he died on 31 December 2019 at 11:11 AM in Arizona, as a result of Lewy Body Dementia.” He had turned 82 years old the previous December (2018) and was about to complete his solar return at age 83 several hours after the moment of his demise. Thus, we must consider his annual profections at age 82, as they were still active at the time of his death.

At age 82 his profected Ascendant in the Gemini-rising chart was Aries on the 11th Placidus house cusp, making Mars the Lord of the Year. Mars is the out-of-sect malefic, and thus likely to be of harm to the native. Natally Mars in Libra squares Asc-ruler Mercury in the Placidus (and Whole Sign) 8th house of death. Mars also rules the Placidus and Whole Sign 6th of illness. In the Vedic system he was in the Saturn/Saturn Vimshottari dasa when he passed. The symbolism certainly fits with the risk of death at age 82 when Mars is activated by profection as Lord of the Year.

If the consider the birthplace solar return which was active at the time of his demise, we see the following:

Noel Tyl’s Solar Return at age 82, active during the year of his demise

In the solar return at his birth place, his natal Asc-ruler Mercury occupies the 8th house of death and conjoins its cusp. The Sun in this return also occupies the 8th house and closely conjoins Saturn, which rules the natal 8th of death. Again, the symbolism generated by the Gemini-rising chart is quite apt for a year in which the native might pass on to the afterlife.

I would argue that Tyl’s Gemini Ascendant produces symbolism far more descriptive of the year of his demise than does the symbolism generated by the Cancer Ascendant. In this case, at least, the geocentric latitude of the birthplace generates a more reliable chart from the point of view of astrological prediction.