I recommend the book: Myths and Symbols of Vedic Astrology. The author explains symbols of the astrological mythology by paying a special attention to the symbolism of cross, circle and arrow. The book is available in pdf.

QUOTES FROM THE BOOK: The cross consists of two lines, one horizontal and the other vertical, intersecting in the middle. It symbolizes the union of Spirit and Matter. The Life-Eternal in Spirit is represented by the ascending line, while Life-Eternal in Matter is represented by the horizontal. The vertical line represents the spiritual male principle, while the horizontal line is the materially creative female principle. Yogic philosophy (Sankhya) describes these as Prakriti, the female principle of cosmic creative energy, and Purusha, the male principle of cosmic awareness. The cross thereby represents the fundamental law of the cosmos. The horizontal line represents Hiranyagarbha, the Golden Egg of Hindu mythology, which is also reflected as Mother Nature and the psyche in man. It contains within itself all the components of the cosmic manifestation; the five prime sensory qualities (lantnatras*), five sense organs (Indriyas**), five elements (Bhutas+) and three prime qualities (Trigunas-n-).

* smell, taste, sight, touch and hearing.

** nose, tongue, eyes skin and ears.

+ earth, water, light, air and ether.

++ Trigunas — Three attributes, viz., Sattwa (harmony), Rajas or activity,and Tamosconsidered as inertia or lassitud“

Under the impact of a planet associated with the cross, the individual changes and radical transformation takes place according to the interplay of spiritual and material forces. In Mercury the cross is at the base, and the circle with a portion of the arc is above it. In Saturn the cross is at the top with the arc below it. The position of the cross on these planetary symbols indicates the nature and significance of the turmoil confronting the individual. Under the Saturn-ian impulse, the conflict between spiritual forces and the material tendencies rules supreme and other forces are subordinated to the conflict. In the astrological context, the cross always signifies some kind of conflict, trial, tension and subjective activity directed towards changing the nature of man and the direction of his course of life.

SEE MORE: https://www.hekme.net/library/books/Horary/Myths-and-Symbols-of-Vedic-Astrology.pdf