Az·i·muth·al Co·or·di·nate Grid
/ˌæz.ɪˈmʌθ.əl koʊˈɔːr.dɪ.nət ɡrɪd/
The azimuthal coordinate grid is essential for locating planets and stars in the sky at a given time and place. Unlike celestial coordinate systems that are fixed against the stars, the azimuthal system is observer-based, meaning it shifts with the rotation of the Earth and the movement of the observer. In astrology, this system underlies the division of the houses, since the horizon and meridian lines—derived from altitude and azimuth—form the framework for how planets are placed in the twelve houses. Understanding this grid helps students see how the “where” of the sky directly shapes the structure of a natal chart.
Source: Cindy McKean
Graphic: Astrologeeks.com