THANKS TO A SENSIBLE order from D.C. Superior Court Judge Gladys Kessler, there is the semblance of an armistice in the long and grubby war between the school board and the teachers' union. So maybe at last the students can enjoy center state. They need i.t Never mind which side thinks it "won" or "lost." The issues that set off this dispute were quickly lost in all the posturing and petulance that robbed the students of 17 days' proper schooling.

That is one reason why the school board members should not appeal the court order. What's left of this school year cannot be squandered.

The first order of business is to catch up. Teachers and principals could perform an important service by issuing short scorecards on the status of each class - what subjects the students have covered and what is supposed to be completed by the end of the academic year. If this were don quickly-what's wrong with by next Wednesday? - students, parents and the schools themselves would have a clearer idea of the time and effort ahead. To his credit, Superintendent Vincent E Reed already has been working on a series of supplemental instructional programs - including individual and small-group sessions - to be offered this spring and summer. Included are tutorial sessions, Saturday classes, work-study programs and other assistance for test-taking and the completion of requirements for graduation.

So where does this leave everything else? After all the havoc, things are back to square one - with the same contract the teachers had before the board tried to change it. For the union, of course, there is the not-so-slight matter of the bill for all this illegal misbehavior. Judge Kessler should insist that fines be paid. As for the strike dispute itsel, if the changes sought by the board were worth this war in the prime time of a school year, the board failed to make the case clearly, if at all. To say this is not to dismiss the board's effort to assert better controls over the quality of teaching. These are entirely appropriate matters for negotiation - and the summer deadlines set forth for this process by Judge Kessler should be taken seriously by all parties.

Not only will there be recommendations from a factfinding panel then, but the contract again will be terminated. At that point the teachers could well face the prospect of losing their jobs if the union doesn't negotiate seriously; similarly, board members would be under public pressure to get their divided act together, and to treat the teachers fairly in pursuit of a timely agreement.In turn, Judge Kessler has been careful to keep the court in this dispute, by ordering all parties to submit progress reports every two weeks from now on.

In the meantime, it would be helpful if the factfinding panel could make some distinctions between those issues that could or might be negotiated with out offers of more money - since the board currently has no authority to negotiate salaries - and those that would best await the board's assumption of some powers in this field.