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Graphing the Natal Chart on a Star Map


The diagram on this page represent my natal horizon system laid out on an equatorial star map. The authors have found that this form of chart representation is very helpful in making clear what the traditional points such as the ascendant, M.C. are. Please examine this map along with the following statements:

  • The straight line through the middle of this map is the celestial equator.
  • The curved line that intersects the celestial equator at 0° and 180° is the zodiac or ecliptic, which becomes a curved line when projected on a two-dimensional surface.
  • You can get a better idea of what the zodiac is by imagining this map wrapped around your head, at which point the curving zodiac would appear at a plane set at a 23 1/2° angle to the plane of the equator.
  • The Local Sidereal Time at my birth was 11h 42m 54s of right ascension along the equator and this is equivalent to a RAMC of 175.70 of arc along the equator.
  • Locate this RAMC on the map.
  • I was born at a geographic latitude of 40° and that is equivalent to 40° declination on the star map.
  • The Zenith or north pole of my horizon system (above my head at birth) points in the direction of 175.70° right ascension and 40° of declination, which is the constellation Ursa Major (the Great Bear).
  • All points along the 175.70° of right ascension were aligned at my birth. Thus I might also look into the constellations Virgo, Crater, Hydra, and Centaurus to the South and the constellations Andromeda, Pegasus, Aquarius, Sculptor and Tucana to the North in relation to my birth.
  • The Midheaven or M.C. at my birth is the point where the RAMC crosses or intersects the Zodiac and this is around 175° of ecliptic longitude.
  • You can see that the M.C. is far to my south and not in my "mid-heaven" at all but rather, the mid-heaven of someone living near the equator.
  • My natal horizon is the long dark curved line running across the map.
  • This line of the horizon is 90° from my zenith and nadir.
  • The intersection of this horizon line to the zodiac in two places defines my ascendant and descendant at 7° of Sagittarius and Gemini.
  • The intersection of the East-West Prime Vertical to the ecliptic defines my vertex (West) and anti-vertex (East).
  • My planets are marked along the zodiac in their approximate positions.
  • As you can see, planets can only be near the horizon at the ascendant-descendant axis.
  • The houses you see in this diagram are the Horizontal House System (I call it the Radiant House system), rather than one of the other systems. In this house system, the anti-vertex marks the cusp of the first house rather than the ascendant, in case you might be getting confused.
  • The points along the ecliptic intersected by these 12 house circles mark the "cusps" or sensitive ecliptic points.


Star Map 1


Star Map 2



© Copyright © 1997 Michael Erlewine







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