C. C. Zain, in his voluminous writings, presented the following paradigm, which I paraphrase:

There are Two Keys, A Golden Key, and a Silver Key, which unlock the Inner Teachings: 

The Golden Key is Astrology, and the Silver Key is the Sacred Tarot.

Gold and Silver, as we know, especially in Alchemical symbolism, and as this symbolism manifested in the archetypes of Depth Psychology in general, and Jungian psychology, in particular, has been associated with the bimodal function of the human psyche.

On an extremely mundane level of generalisation, we could say that Astrology is a Rational Science, while the Tarot is Intuitional. Again, these systems are believed to operate from separate hemispheres of the brain. Therefore, by analogy, and in a rough outline - we could say that the Sun Sign,  or the Sign the Sun is in at the time of our birth,  represents Astrology, while the Moon sign, represents the Tarot. 

We have inherited, through almost seven thousand years of accumulated cultural heritage, a visual transmission that is associated with Astrology, and more recently, through the images of the Tarot. 

These two visual streams are not identical. In many cases, they seem incompatible to each other. But these are surface observations. For example, the image of the Zodiacal Sign, Aquarius, is a Youth pouring forth liquid from a vase; while in the Tarot, the image that associates with Aquarius, is an Old Wise Man, the Sage or Hermit.

Here we have a polarity - in this case, of Puer and Senex, Youth and Age.

Pisces presents us with Two Fish in Astrology, and a Hanged Man, in the Tarot. And so on.

We are fortunate in that at present there is some amazing research on the History of Astrology being published. Much of this material is only available in very learned Journals, but a great deal has become available on open access on the Internet.

It seems obvious to me, that we are all conditioned in our understanding and approach to Astrology. Many highly intelligent people only see Astrology through the lens of the vulgar  Press releases. It is trash,  unscientific and so on. The stupidity of this point of view is astounding. 

On the other side of the equation, we have the Astrology for the Millions phenomena, which at its lowest common denominator, descends into the trash of the daily newspapers. But there is nevertheless a high quality of material available, also in publication, by reputable publishing houses, such as Routledge &c.