The Washington Capitals take their six-game unbeaten streak to the badlands of Alberta tonight, beginning a challenge that many teams would consider impossible.

The first obstacle is the Calgary Flames, whose 26-12-4 record is the best in the National Hockey League. It is a battle between the stingiest team in the league, with Washington yielding only 127 goals, and the most prolific, Calgary having scored 207.

With hardly time for a breath of chilled air, the Capitals on Monday move up to Edmonton to take on the defending Stanley Cup champion, the No. 2 offensive club in the NHL.

The schedule maker found it convenient to assign eastern visitors to these far-off cities on a single trip. The arrangement has been less favorable for the teams themselves, however.

Over the last five years, only one club, Washington, has managed to win in Edmonton and Calgary on the same trip. The Capitals did it last February, although the games were set a week apart.

Before that milestone, no visitor had gained an Alberta sweep since Quebec in November 1982. The last team to beat both on successive nights was the New York Islanders, Oct. 7-8, 1982.

The Capitals were feeling good when they left Washington yesterday, after Friday's 8-4 blowout of the New York Rangers, and they were primarily concerned with Calgary, a team they have beaten only once in the last seven tries.

The Capitals have enjoyed dissimilar fortunes against Edmonton, winning seven of the last eight, including two Capital Centre victories this season. Besides, Wayne Gretzky is nursing a sprained knee and will be unavailable Monday.

"Calgary and Edmonton are just about 1-2 in the league right now and for us there's a plus and a negative," said Mike Gartner, Washington's leading scorer. "We always seem to have success against Edmonton and we always seem to have trouble against Calgary. If we could come out of that with three points, I'd be extremely happy."

"We have a good idea what Edmonton has, because we just played them (a 2-0 triumph Jan. 2), but we haven't faced Calgary for a while," said winger Bob Gould, who scored twice against the Rangers Friday and who broke into the NHL with the Flames. "Calgary has big forwards and they're good skaters, not big and slow, but big and fast.

"It'll be a test for us. We had a letdown and made mistakes after we got ahead of the Rangers. We can't do that in Calgary. We'll need one of our best games to win there."

Greg Adams, whose ninth goal broke open Friday's game, said, "I guess you can call this a roll we're on, losing only one of 11. And we should have had that Philly game (a 3-2 loss Dec. 26). We had a 2-0 lead and we just messed up in one period.

"We've been executing our whole game better, all the little things that add up to a roll. And we're winning in different ways. One night it's {goalie} Clint {Malarchuk}, another night it's Garts {Gartner} with a big goal and last night we had three or four guys scoring goals who don't normally score a lot."

A major difference between the Capitals of today, fighting for the Patrick Division lead, and last year's club that was six games under .500 and struggling to escape the cellar in January, has been the contribution of Gartner.

Gartner currently leads the team with 24 goals and 42 points and his plus-six rating is tied for third. That is quite a contrast to Gartner's figures after 42 games a year ago.

At that time, he had 10 goals and his rating was a horrible minus-15. Yet he had put 159 shots on goal, just one less than his current figure.

"I keep plugging along," Gartner said. "I started off pretty good, went through a seven or eight-game drought and since then I've picked it up. I'm contributing offensively and I'm helping out defensively. I'm trying to do my job and I know the priority is to get a goal when goals are needed.

"I didn't do that last year. I was working hard and getting just as many chances, but I wasn't scoring. I'd never been through anything like that. It taught me lessons and made me a better hockey player. I had to tighten my defensive game, because I wanted to help the team and I wasn't doing it offensively."

Gartner finally caught fire last year, collecting 31 goals in the last 35 games and leading the Capitals to a second-place finish. If he can come close to that stretch drive, he would become a 50-goal scorer for the second time and Washington might finally wind up first.

Gartner was a key figure in Canada's victory over the Soviet Union in the Canada Cup and he has been on the ice since Aug. 5. Accordingly, he foresees a hurdle of sorts in the next few weeks.

"Within the next three or four weeks, the season will feel pretty long and there may be a time where we'll need two or three days off. I think management is aware of the situation and they're leaving it up to us to let them know.

"I can't complain, because there sure were a lot of positive things. I started the season in great shape and I was on a mental high. But the 80-game schedule wears quite a bit."

Capitals Notes:

Goaltender Pete Peeters, who last played on Dec. 26, when he suffered a pulled thigh muscle, is scheduled to face Calgary, with Malarchuk starting in Edmonton . . . After spending eight hours in cross-continent travel, the Capitals practiced at the Olympic Saddledome yesterday at 6 p.m. MST.