Tarot readers use many different tools.
Astrology is a vast science. It takes many years to master the craft of this and be able to use it for tangible readings. However it is not just limited to advanced science readings. Its imagery is rich with details that can be colorful in meditation. In fact, a steady structure in meditation is what is desired in order to bring a level of attunement.
Astrology can also be used as a spiritual tool for attunement. There are many meditations that use the phases of the Moon each month. For instance the major angles of it form an eight rayed star, which is the most radiant of star in the cosmos. This is the shape of all things in manifestation. Mystical things and intuition exist because of the connectedness of all things. The entire universe is made up of elements that move in patterns. These same elements and patterns are within us and within all of life. All of life moves together.
A favorite meditation of mine is based upon a lovely scene I saw many years ago. Imagine sitting on a hill where the Sun is just behind you. Then in front of you, a large white, Full Moon in a blue rises. Breathe in and let the Moon shine. A quiet curtain of fireflies is spread out and glitters atop the gently swaying becoming brighter as the radiant Sun has fully set. Breathe deeply. The whole sky beneath is a living canvas of sparkling jewels. Keep your eyes closed and let your mind expand from horizon to horizon.
In Tarot Phases of the Moon (waning/ axing) can be a vital role in when to meditate whether it is the first quarter, Full Moon, third quarter or New Moon.
Enjoy your card reading!