Throughout history astrologers were famous for being poor. But today it is possible to make a satisfying living at the craft. Astrologers say it is not uncommon to earn $20,000 to $50,000 a year. The biggest dollars are in financial astrology - predicting which stocks or commodities are best to invest in. Bill Meridian, who is a Wall Street specialist, said its most successful practitioners can earn at least $100,000 a year.

They can make piles more if they trade effectively on their own predictions. Sometimes, of course, they mess up. ''Last year, I was under affliction by Pluto, which is bad for trading,'' Mr. Meridian said. ''But I tried a few trades anyway and got my head handed to me.''

Some people who do financial work, like David Williams of Clearwater, Fla., (see box) work up astrological charts of companies based on when they were incorporated, which is the equivalent of when they were born. (Remember, nobody said you could do charts only of people. An astrologer named Debbi Kempton-Smith, in fact, once did a horoscope of the Empire State Building. She found out it was a jealous building that probably got terribly anxious when the World Trade Center went up.) Doing companies, however, can get tricky, since you need the exact time that a corporation was born. Most states do not record the time on the incorporation documents. Happily, Delaware, where many companies choose to incorporate, does mark down the moment within 15 minutes, which is better than nothing.

While many astrologers devote tedious hours to figuring out things like where Neptune and Jupiter were at 4:06 A.M. on April 8, 1934, and what that means for someone, a great many others do little more than take their best guess about peoples' futures. There are charlatans in a lot of fields, though astrology runs a fairly high incidence of them. A big part of the problem is that astrologers generally are not required to be certified in any way. Only a few cities, including Atlanta, require a review of astrologers' qualifications (though if you pass an all-day test, the American Federation of Astrologers will hand you a certificate that says you are a professional astrologer). ''A lot of young people today read two paperback books and declare themselves astrologers,'' huffed one astrologer. ''It's ridiculous.''

It can be hard to test astrologers, because much astrological guidance is general in scope or of the don't-do variety. If you follow the advice and do not do something, there is no way of knowing what would have happened if you did do it. Astrologers, on the other hand, complain that the big reason they get a bad name is many people don't understand what astrology is all about. ''A lot of people want to know the usual nonsense things - when am I going to make a million dollars or when will I meet Mr. Wonderful,'' said Leslie Presser, who does therapy with drug addicts at a New York rehabilitation center and reads horoscopes as a sideline. ''That's not what I'm about. I'm about trying to help people understand their self.''

When you are not visiting your astrologer, there are many other ways to spend money on astrology. Besides innumerable astrology books, the field supports around 20 magazines, like Horoscope, which bills itself as ''the world's leading astrological magazine''; American Astrologer; Astrology Guide and Astrology. In addition to offering daily advice, the magazines run sundry feature articles illustrating how astrology has affected peoples' lives.

For instance, the new summer issue of Astrology Guide details how Mitchell Drummond followed the magazine's advice that you could improve your odds of winning games of chance by playing only when the sun is in a sign element that is in harmony with your birth date. He won $454,434 in the California lottery.