Sunspot activity will increase in the next few weeks, and that won't be good for the stock market, said Arch Crawford, a New York astrologer who's gotten lots of publicity because of the patterns he claims to have detected between activity in the heavens and on Wall Street.

Crawford is one of the more colorful "cyclists" who spend their days trying to predict what patterns the stock market will follow based on what it has done in the past. Crawford claims that the higher the level of sunspot activity, the greater the possibility of trouble for the market.

In fact, many of the cyclists today are predicting that the stock market is in for very rough times, although they disagree as to the exact timing.

Considered just short of voodoo by many on Wall Street, cyclists of all kinds still manage to have a fairly wide following among professional investors.

Most of the cyclists -- unlike the stargazing Crawford -- don't get much publicity. Their work is extremely esoteric and difficult to explain to the average investor. And members of the press tend to prefer dealing with more easily understood concepts like interest rates, recessions and, yes, even program trading. But the cyclists are undeterred, and they toil away at their mathematical formulas and pricey newsletters.

Why would anyone who isn't a kindred spirit of Shirley MacLaine listen to a person who said that the stock market does what the stars tell it to do? Or listen to someone who claims that stock prices move in predictable 40-year cycles?

The answer is simple: Investors listen because they want every advantage they can get, and the cyclists can be right.

Crawford, for instance, accurately warned people just days before the 1987 crash. And you don't have to have too many correct calls like that to win a following.

"A lot of people think cycles are some kind of magic," said Richard Mogey, executive director of the Foundation for the Study of Cycles in Irvine, Calif. "But as we do cycles, they are strictly history. They are what happened."

Mogey said his organization was founded 50 years ago by Edward Dewey, who was asked by President Herbert Hoover to do a study of what caused economic depressions. And what Dewey and his successors discovered is that the economy and financial markets seem to follow a repeating pattern.

For instance, Mogey's foundation said there is a major drought every 60 to 80 years that raises food prices and interest rates and causes an economic slowdown. Cycles like this are rooted in fundamental economic factors. "It's not mystical," he said.

The foundation also believes that consumers behave cyclically. They will remain confident for only so long before they start questioning how much further their good luck can hold out. That's when they begin to pinch pennies, and an economic downturn starts.

Peter Eliades, a disciple of Dewey and author of Stock Market Cycles newsletter, is one of the better known cyclists. And what he is predicting right now for the stock market isn't pretty -- a level of 1000 for the Dow Jones industrial average in 1992 or 1993. There's no prestidigitation here. Eliades said the research that came up with that conclusion is based on history.

"The big decline should start by the end of this year," he said. He believes the market is now replaying a recurring 876-week cycle between the peaks in prices -- or market tops, as he calls them. Despite the Dow's recent ascent near 3,000, Eliades thinks the top for the market as a whole was actually reached last October. At that point, small capitalization stocks started drifting lower.

It would be easy, of course, to predict what the market was going to do if the only thing required was to count up to 876 weeks. Eliades claims, however, that when you look back at stock prices into the early 1800s, there are other cycles that overlap, conflict and complement the 876-week cycle.

There are 60 to 70 different market cycles in all, Eliades said. One of those cycles, he said, shows that an important low for the market occurs approximately every four years. This cycle is also due in 1990-91.

All of the cyclists, of course, think there will eventually be a downturn in stock prices. If prices didn't eventually turn down, there would -- after all -- be no cycles. But a large number of the cyclists are currently carrying placards that read, "The End Is Near."

Walter Studnicki, who writes a newsletter called the "Turning Point" from Scottsdale, Ariz., said he used cycles that he developed based on the work of a 19th-century trader and the work of a mathematician from the Middle Ages. His formula says that stocks peak every 40.68 months.

The market should be reaching a top price on Dec. 14, Studnicki predicted. But he hedged this bet by saying that a conflicting cycle may delay the onset of the next bear market until the first quarter of 1991.

By 1992, Studnicki believes, the Dow should be in the 1500-to-1700 range.

Michael Jenkins, author of Stock Cycles Forecast in New York, on the other hand, thinks the Dow will start a 1000-point fall as soon as the current market optimism starts to wane. And the optimism, he said, could start eroding as early as this week.

Jenkins, who uses complex mathematical formulas to predict market patterns, believes the Dow will eventually settle around the 1400 level. That could take two to three years.

"The current Dow pattern seems to be following a pattern that is eerily similar to both 1987 and 1929, and both ended in complete collapses of the stock market," Jenkins said.

"There is room," he added, "for the market to stay aloft into late September." He said that his work has allowed him to predict every major high and low in the last five years.

The most famous cyclist today is probably Robert Prechter, proponent of something called the Elliott Wave Theory. Prechter is taking a much lower profile these days than he did back in the mid-1980s when his predictions could have a profound effect on stock prices. But he is still followed widely.

R.N. Elliott, an accountant who died in 1948, actually developed the theories used by Prechter to predict the market.

Studying the effects of the 1929 crash and its aftermath, Elliott theorized that crowd psychology in the stock market developed in predictable trends and reversed itself in chartable patterns. There was an "up" leg in stock prices followed by a "down" leg, followed by up and down legs and one more up.

Dave Allman, Prechter's director of research, said the fifth wave is now coming to an end and will bring a large correction.

John Crudele is a columnist for the New York Post.