This is also to lunalafey
Lunalafey -- a quick note. I too read Joseph Goodsavage's book as my first text on astrology. A co-worker noted my reading of the book during lunch break and asked me to do his horoscope. From that little paperback, and by scaling the simple planet position lists given to find approximate/exact placements, I wrote out my observations. I was correct, having described three periods of illness that impacted his diet and outlook. I even described what he couldn't eat. I only held back one thing. Several months later he died from MS -- within a day of the time I had plotted out.
NOW, I had only read the book to prove to my wife that astrology was useless. After that, I did not do charts for anyone for a year but did I study every book I could buy.
IS ASTROLOGY VALID? To answer the question that started this tread -- it something you have to prove to yourself. Do I know it works -- emphatically. Do you know? That is YOUR question and its only for you to answer. I do know these things:
1) You can do astrology using standard meanings for each planet, sign, house and aspect but it only generally fits.
2) You can be an expression of astrology and it will speak through you and be as accurate and specific as your confidence, skills and understanding of it will support. It can intuitively just flow through you.
3) Your articulation of an astrological chart reflects only your level of knowledge, your ability to love and relate, your experience in living life. Your words will be both similar and different from those of every other astrologer. When any of reads what another astrologer writes we recognize both the common and the differing views -- and accept them, generally. They are just another view that we can understand but may not be able to express in that manner.
4) The people and situations that come to you will mirror your level of capability and views of life. When someone comes to you who makes you uncomfortable or who asks to much, throw your arms open and rise to the challenge. Everyone you meet has some hidden message that you need. Embrace change and challenges in order to be a better astrologer.
5) When you are asked if "you believe in astrology" say no but I believe in the astrologer. The magic is in the person, not in the chart.