Many individuals who become serious about astrology seek a spiritual connection with it. Many will find a way to include astrology into their preexisting philosophical or religious ideas and others will allow astrology to alter those ideas.
While magic has a negative connotation in contemporary society (either being ridiculed by science or condemned by religion), theurgy is one of the great Hermetic arts that are said to unite individuals with god. Astrology and alchemy are the other two, so it's no coincidence that astrology became both a vehicle and mechanism for magic.
Astrological magic seeks to combine physical objects with astrological power through the utilization of electional techniques, planetary sympathies, and invocation. The goal is to produce a physical object (often referred to as a talisman) that will radiate an effect given to it by the power of the planets or other celestial entity imprinted on it at the time of its creation. This process immortalizes fortuitous elections and attempts to prolong their effects on individuals.
This spiritual, magic power is thought to exist in nature and is utilized to some extent by many religious traditions. Healing stones, gems, metals, and herbs are manifestations of the astrological magical world. The cosmos is thought to be a series of links that form spiritual chains between superior and inferior bodies. There is one chain for each of the planets, and every object and concept exists in one or more of those chains. Each lower link of the chain draws its power from a higher link so that every thing that exists in all of creation draws its power or likeness from a planet.
It was thought, then, by combining different parts of a chain together and affixing an object with a sigil, symbol, or image at a properly elected time an individual could infuse that object with celestial power to fulfill a certain task. This could be the preservation of health, accumulation of resources, or protection from misfortune.
Astrological magic has a great position between electional and natal astrology. For those students who are open to this branch of the art, it offers another way to use skills gained in electing charts by slightly shifting the focus or intent of the election. Those not interested or feel the philosophy in magic contradicts their idea of astrology are free to move on to other branches without fear of missing too much practical information.
"Indeed all sages agree in this, that the planets have influence and powers in this world, by which all things are made and transformed by the movement of the planets in the signs. For this reason sages understand that the foundation of magic is the movement of the planets."
-Picatrix, Book II, Chapter I