Complex sentence: Horoscopic astrology is a form of astrology which uses a horoscope, a visual representation of the heavens, for a specific moment in time in order to interpret the inherent meaning underlying the alignment of the planets at that moment.
Split into simpler sentences: Horoscopic astrology is a form of astrology which uses a horoscope, a visual representation of the heavens, to gain information from the position of cosmic bodies. It dealt largely with horoscopes cast for specific moments in time in order to interpret the inherent meaning underlying the alignment of the planets at that moment.