The sun begins to set on “Downton Abbey” at 8 p.m. Sunday as the popular PBS series’ sixth and final season premieres on WYES-TV.

“Nobody wants to see that show end,” said Tim Lantrip, proprietor of Covington’s English Tea Room & Eatery and a fan of the series. “It’s been such a great show. They’d like to see it continue, but all things come to an end.”

As the new season begins, estates like the fictional Downton, portrayed on screen by Britain’s Highclere Castle, are entering the twilight of their centuries of occupancy by English aristocrats.

Robert and Cora Crawley, the earl and countess of Grantham (played by Hugh Bonneville and Elizabeth McGovern), are managing the entropy that befell great country houses like their own as the 20th century progressed.

The sometimes soapy affairs of daughters Lady Mary Crawley (Michelle Dockery) and Lady Edith Crawley (Laura Carmichael) continue, as do the astringent asides of Robert’s mother Violet (Maggie Smith), the dowager countess of Grantham.

Also swept up in history’s inevitable advance are the estate’s downstairs servants, whose lives sometimes reflect the melodrama playing out above them.

George L. Bernstein, a Tulane University professor who specializes in the political history of 19th- and 20th-century Britain, will be watching Sunday night, or at least recording the episode for later replay due to its scheduling conflict with “Sunday Night Football.”

Bernstein said he’s “very comfortable” watching British costume dramas.

“Unless something is explicitly historical, in which case I start being bothered by all the things that aren’t historically correct,” he said. “I was with this (series) from the beginning. In the first season, when the Turk dies (in Lady Mary’s bed), that got me. After that, I was hooked. I think it’s been good. But I’m glad they’re stopping it. I think it’s beginning to run out of steam a little.”

Also watching or recording every episode of the final season will be New Orleanian Jennifer Rareshide, who has enjoyed following the series with her family.

“We, for sure, as a family will be sitting down to watch it,” she said. “It was a neat way for my daughters to tap into history in a fun way and not from a more boring, dry history book.

“Then there’s the suspense element: ‘What’s going to happen? Who did it?’ ”

To Rareshide and no doubt many others, one of “Downton’s” appeals is its time-travel depiction of the manners and mores of a long-faded era.

“The way the family, even though they have their issues, they’re always there together for dinner and things, really communicating as a family from one generation to the next,” she said. “The elegance, the respect. How (the characters) present themselves” and “conduct themselves in the changing world.”

A co-production of Britain’s Carnival Films and PBS’ “Masterpiece,” “Downton” is the most-watched drama in PBS history, attracting an average of nearly 13 million weekly viewers during season five. Sunday, PBS sends it off with the wrap-around specials “Countdown to Downton Abbey” (7 p.m.) and “Downton Abbey: A Celebration” (9:15 p.m.).

Public and private bon voyage fê tes — appropriate for a show that incorporated news of the Titanic’s sinking into its premiere episode — will continue as the March 6 series finale approaches.

WYES plans a fundraising gathering — period dress encouraged — at 2 p.m. Jan. 14 in a private home in New Orleans. Lantrip’s British tea room has a celebration scheduled for 7 p.m. Feb. 19.

Such tea room gatherings in the past have sold out swiftly, Lantrip said, and about 80 percent of the attendees have worn period attire.

Guests pose with life-size cutout photos of the show’s characters, he added, and the menu includes some of the dishes served to the Crawleys by their attentive servants.

“We encourage people to dress like they do on the show,” said Lantrip, who dresses for “Downton” events as the show’s by-the-book butler, Mr. Carson. “We serve food directly off the show menu.”

Rareshide, who has attended past WYES “Downton” events, said costume choices for lady attendees have expanded in variety as the show’s timeline moved from the Edwardian era to the Roaring ’20s.

“What’s neat now is that you can pick what period you want to dress from,” she said.

“Downton’s” final season has already aired in England, so fans should eschew Google to preserve its secrets. They also should avoid, at least until Monday, friends who’ve attended any of the several advance regional screenings of Sunday’s episode that WYES has presented from Houma to Biloxi, Mississippi.

Sunday’s episode is the first of the final season’s nine episodes. “Downton” creator Julian Fellowes is reportedly working on a script for a feature-film reunion, but nothing official has been announced so far.

Though she’ll miss “Downton” once it’s gone, Rareshide said the time to close out its story — pending a possible movie — feels right.

“They’re kind of getting out of those interesting, elegant, beautiful years,” she said. “How would they represent Downton Abbey in the 1960s and 1970s?

“The show is really about the old history. They’re getting too close to our modern world, and I just don’t think it would work.”