The National Academy of Sciences has asked the Soviet Union to allow an American legal observer to sit at the trial of soviet computer scientist Anatoly Scharansky.

In a cable to Soviet President Leonid I. Brezhnev, Academy President Philip Handler formally requested permission to sent "one or more distinguished American attorneys and legal scholars" to the trial of Scharansky, who has been accused of treason. Handler mentioned in the cable three prominent U.S. law professors and two judges (including U.S. Court of Appeals Judge David L. Bazelon) who would be willing to take on the assignment.

"Future relations between the scientific communities of our two counties could well be affected by world opinion of the fairness of that (Scharansky's) trial and its outcome," Handler said in his cable to Brezhnev. "It is therefore in our mutual interests and certainly in the interest of Dr. Scharansky that there be appropriately qualified legal observers at his trial, free to report their observations subsequently."

Few Soviet violations of human rights have stirred American scholars like the ease of Scharansky, an active dissident who was arrested in March when a Soviet newspaper accused him of working for the Central Intelligence Agency. Nobody in his family has seen or heard from Scharansky since his arrest. He is presumed to be in a cell in Moscow's fortress-like Lefortovo Prison.

No formal charges have been made against Scharan sky, but it has been widely reported that he is under investigation under Article 64 of the Criminal Code of the Soviet Union. That article, involves high treason, which carries a minimum punishment of 15 years in prison and the threat of death.

The most recent statements by the official Soviet news agency Tass suggest that the charge against Scharansky might be dropped to an indictment under Article 70, which is anti-Soviet propaganda activities. That carries a minimum sentence of six months and a maximum of seven years in prison.

Scharansky, a Jew, is also one of the "refuseniks," meaning he has been denied on exit visa to emigrate to Israel. Scharansky was first denied his exit visa in 1973, then denied it four more times on grounds that he was involved in secret research. He was dismissed from his job at the All-Union Scientific Research Institute of Oil and Gas in 1975.

In the two years after he lost his job, Scharansky became one of the boldest and most articulate critics of Soviet injustice. Fluent in English, Scharansky acted as spokesman with Western correspondents for all "refuseniks" and served as an active monitor of Soviet compliance with the Helsinki agreements on human rights.

No date has been set for Scharansky's trial, since no formal charge has been made against him.

Handler clearly went to great pains in the cable to state his concern about the trial's impact on scientific relations between the United States and the Soviet Union. Of the estimated 2,000 scientists who have been exchanged by the two countries in the last 15 years, half were arranged in the United States by the National Academy of Sciences.Most of the rest were administered by the State Department.

In asking for permission to send at least one legal observer at Scharansky's trial, Handler said that, in addition to Bazelon, the following had volunteered: law professors Leon Lipson of Yale, george Fletcher of the University of California and Alan Dershowitz of Harvard, and Court of Judge Damon J. Keith from the Sixth Circuit Court of Appeals in Cincinnati.

Handler said it was not a precedent to ask to observe what many consider to be a trial of human rights.

"You will recall, Mr. President," he said in his cable to Brezhnev, "that when Soviet citizens express concern for the fate of Angela Davis, President Nixon personally authorized an invitation to 14 Soviet scientists to attend her trial.