It won't take Joe Gibbs very long to discover the magic and madness that is a Redskin-Cowboy game.

For the second straight season, the Redskins will open their schedule against the Cowboys at RFK Stadium, but unlike last year the game won't be part of the NFL's Monday night television package.

The contest will be held Sunday, Sept. 6, at 1 p.m. and will be the first of four straight games for Washington against NFC East Division rivals. An RFK Stadium game against the New York Giants is next, followed by games in St. Louis and Philadelphia.

Washington's disappointing record last year and mixed prospects for 1981 are reflected in the schedule, which was released yesterday by the league.

The Redskins will not be in any Monday night games, the first time they have not appeared in the ABC-TV series, since it made its debut in 1970. Washington has one of the best Monday night records in the league, 12-6, even after losing to Dallas and Denver last season.

But ABC and the league prefer to feature what they believe will be the best teams on the Monday night telecasts. And Washington isn't considered in that class anymore, after falling to a 6-10 record last season.

The NFL and the other two networks, NBC and CBS, also limited Washington's national exposure on Sundays. The Redskins will appear as the second half of a Sunday double-header -- the late game normally is shown nationwide -- three times. In 1980, they had four second-game appearances, plus a national Saturday game against the Giants.

Although having Dallas as the opener obviously will provide an incentive in training camp, the Redskins found out last season that meeting the Cowboys so early can backfire.

Jack Pardee's team pointed so much toward the Monday night game that when Dallas won, the Redskins suffered a letdown that contributed to a 1-5 start. Many of the roster decisions that Pardee made also were influenced by having to play Dallas so early, a factor in his eventual firing.

Gibbs, who says it is imperative for his team to win at home against Dallas and Philadelphia, observed yesterday that playing four division opponents so early "puts a different light on things, preparation-wise.We better be ready to go right away.

"I don't know what the Dallas game is like, since I've never played them here.But I guess this is one way to find out. I want to approach it just like I would any other game; that is, we have to put the same emphasis on all of them because they all count the same.

"Can that be done? It's something I'm going to have to find out. I know there is a special feeling for the Cowboys around here, but I'll just have to see what happens."

Gibbs, who came here from San Diego of the AFC, said the schedule helps in one way. "I'll certainly find out in a hurry what our division is like."