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dadsnook2000  dadsnook2000 is offline
Join Date: 30 Apr 2003
Location: Massachusetts, USA
Posts: 3,474
Some comments

This subject of spherical geometry and its impact on charts is a very large subject. I will attempt to reduce it to its bare minimum, always a dubious course of action.

NATAL charts are really models that include some"actuality" in the sky patterns and much that cannot be seen such as sign boundaries, houses, etc. If the model works, it works.

Once we "MOVE" or "ANIMATE" the chart in some way we start to encounter issues related to spherical geometry. We all know this. Because of the inclination of the equator to the ecliptic, there are places and times when one's positional calculations (by hand or computer) yield distortions of one kind or another. An example is that one sees the Moon at the Descendant angle in a chart, yet due to its its orbital position relative to the nodal axis it is really out of sight below the horizon at the chart's calculated time --- it's actual position being "projected" upward by the calculation to the ecliptic where we measure our longitudinal position (zodiac), different from the equator where we measure our locational position.

This is one reason why many astrological programs offer a speculum table --- it calls our attention to these spherical geometry issues. OUR EARLY STUDIES LIST MEMBERS should look at these rising-setting-culminating tables to find instances for themselves. Latitude matters --- the questions are A) by how much, and B) should you care? Dave
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