I fell in love with astrology and mythology years before I touched my first tarot card; I spent my adolescent years reading every astrology book I could put my hands on (and started with tarot only as young woman). In spite of my problems with maths, I had fat books with formulas and made everybody's birth map... loved it.
That knowledge sunk deeply, I'm far from versed in astrology and would find it difficult to interpret a birth chart today - but I still draw on my knowledge of planets and signs. I feel it helps to know the character of Sagittarius when I think about Temperance. And for the minors, the decans are definitely helpful.
It also helps to get a deeper understanding of the elements. Think of Fire. There's the initial burst of energy - that's Aries. There's the reliably burning flame - that's Leo. And there's the glowing warmth with sparks - that's Sagittarius. So what kind of element do we see in each card? The astrological attributions help.
BUT only if you're interested in astrology. I have always been fascinated with it, and for me, it's interesting stuff. I'm sure alchemy would help me tremendously but it doesn't fascinate me. So I read some books about it but my memory didn't hold on to it, and it's not useful to me.
So decide for yourself, give it a try. Either it resonates with you, then it's great. But if not? You can still be a great tarot reader without it.
The best book about tarot and astrology IMO is by Anthony Louis. I did read Ruth Aharoni and another one, can't remember the name, but Louis is really great.
Btw, I personally am also very interested in astronomy and am an avid stargazer. Seeing all the constellations of the zodiac actually in the sky over the course of a year is a humbling experience. Some of them you can really SEE: Scorpio, Taurus and Leo really LOOK like a scorpion, a bull or a Lion. Others are more difficult to see. But they're all wonderfully beautiful, and you see their path on the sky, always the same, where also Sun and Moon travel, and you feel connected to generations of humans.
These are not some theories someone invented once. These are about the first things humans noticed when they lifted their eyes from the earth. The stars and constellations, star observations and star lore are the seeds of all science, belief and culture.
So astrology IMO is not some sordid charlatanic business (although it can be and undoubtedly often is) but the deepest layer of knowledge and awe in all human cultures. So definitely worth getting to know not only for tarot but for its own sake.
IF you want to, of course.
