‘SINS’ VS. ‘PETER’: THE ENVELOPE, PLEASE . . .

Joan Collins’ “Sins” on CBS opened its battle Sunday with the rich Russian history of NBC’s “Peter the Great,” and when the smoke had cleared Monday, overnight ratings for the first round in the war between the miniseries showed Peter the greater in terms of audience.

“It looks pretty clear that ‘Peter the Great’ won the battle, but not by an overwhelming amount,” CBS research vice president Arnold Becker said Monday, referring to the 12-city preliminary ratings for the two costly, heavily publicized programs.

National ratings are due today. But they aren’t expected to change the victory won by NBC in Sunday’s overnight A.C. Nielsen ratings for 12 major markets, which include New York and Los Angeles and represent a total of about 27 million households.

CBS’ “Sins” began an hour before NBC’s “Peter” on Sunday. But NBC clearly seemed to have foiled CBS’ effort by airing a special half-hour episode of its hit “The Cosby Show,” followed by “Amazing Stories,” opposite the start of “Sins.”

The 12-city ratings averages showed that NBC’s combination of “Cosby,” “Amazing Stories” and “Peter the Great” were the night’s winners, averaging a 23.9 rating and 34% of the audience, compared to the average 18 rating and 26% audience share recorded for CBS’ three-hour debut of “Sins.” A rating represents the number of sets tuned to a particular program; the share represents the estimated percentage of the audience watching that program at a given time.

According to overnight ratings for the two hours that “Peter” and “Sins” were in direct competition, NBC’s entry averaged a 23.1 rating and a 33% share of the audience, while “Sins” averaged an 18.6 rating and a 27% audience share.

ABC’s offering in that two-hour time period, “Octopussy,” a 1983 James Bond film making its first appearance on network television, came in third, getting an average 16.7 rating and 24% of the estimated audience.

NBC’s opening-night victory gave the resurgent network another push in its bid to end this season as first in prime-time ratings. CBS, now second in season-to-date ratings after six seasons as No. 1, still hopes that “Sins” and its other programs this winter and spring will help it stave off an NBC victory.

The three-night run of “Sins” concludes tonight, while “Peter the Great,” a four-part miniseries, ends Wednesday night.

The two programs were their networks’ opening blasts in the key February ratings “sweeps,” a period of intense audience measurement that determine local advertising prices set by TV stations throughout the country.

There are four such sweep periods a year. The current one began on Jan. 30 and will end on Feb. 26, a Nielsen spokeswoman in New York said.