The Tabernacle cupola is undergoing the most significant restoration in more than a century. The $635,000 project will not only preserve the cupola for the years ahead, but restore its key purposes of ventilation and visual distinction.

For Russell E. Dagnall, president of the Martha’s Vineyard Camp Meeting Association, the work, called Topping off the Tabernacle, is but part of a much larger $3 million restoration of the Tabernacle that began almost 10 years ago.

While the restoration of the Tabernacle has been extensive and expensive, what is happening now is the most visual aspect of the work on the wrought-iron outdoor theatre, for the cupola can be seen all around its hometown of Oak Bluffs.

The cross on top, which has glowed for 38 years, is about to be taken down. With the demolition nearly complete, the rebuilding of the cupola will begin in the New Year.

No one is alive today who can remember the way the cupola looked as it was intended. There are photographs and they are old. And since there have been restoration efforts throughout the Tabernacle’s 128-year history, Mr. Dagnall said the association has chosen 1901 as the signature date for the whole restoration project.

“The last big restoration was in 1901. That was the last time there were any significant structural changes. At that time they built the front entrance,” Mr. Dagnall said.

The cupola of 2008 will look more like the cupola that was originally built on the Tabernacle than the most recent cupola, built principally of wood panels, that is being taken down.

Earlier this week the cupola looked like it had been completely removed, because the wrought-iron skelton blended in so well with the scaffolding.

Project superintendent Ralph Gillespie said the bolted iron beams and columns were in perfect condition. The iron will be scraped and repainted.

The new eight-sided cupola will be made of metal sheathing by Crocker Architectural Sheet Metal in North Oxford. Much will be fashioned there at their plant based on the old cupola. And each side will have large louvres to allow warm air to rise from and exit the hall.

The cupola by itself is a curious structure, its interior size almost like a belfry.

“Nobody knows whether the cupola was constructed along with the Tabernacle or whether it came from somewhere else, or whether it was once atop another building,” Mr. Dagnall said.

If one were to describe the Tabernacle, it is a big wide-brimmed Easter bonnet and the cupola represents the ornament, the flower on the top that makes the building distinctive.

The cupola is a fashion statement and Mr. Dagnall said the association has received a lot of commentary from those who care just about how it will look when finished, especially the cross. The top of the cupola is 75 feet above ground.

When the cupola was first built, a tall flagpole rose high into the sky. It likely flew a huge Methodist flag, not an American flag as one might think, Mr. Dagnall said. The remnants of that pole resides inside the cupola, but the top of it is long-gone.

The one significant change to the historic Tabernacle represents a departure from the past, a merger between today and yesterday. Instead of installing a flag pole like the one initially there, a cross will be put in its place.

The cross now atop the Tabernacle will come down on Wednesday, the day after Christmas, according to Mr. Gillespie.

Its removal is significant, for it will be the first time a cross has been taken off the Tabernacle deliberately. The two previous ones came down in bad weather. The first went up around 1926 and unexpectedly came down in a hurricane in 1944. The second cross came down in a winter storm in the late 1960s.

The new cross will be twice as high as the one there now. The carbon-fiber cross, which will rise 20 feet above the cupola, is being manufactured by Halls Spar & Rigging of Bristol, R.I.

Unlike the present cross, which was lit inside by 33 40-watt lightbulbs, the new cross will be taller and thinner, like a mast, and be illuminated from the outside by lights shining up from the roof.

The asphalt shingles on the roof of the cupola will be removed and replaced with a zinc-plated copper sheathing. By appearance it will be historically authentic, but the installation will be more environmentally friendly, without lead.

For the architect, Martha Wrenfels, a project of this length isn’t unusual. Historic restoration projects do take a while.

“I was involved in the exterior restoration of the Rhode Island state capital and that took four phases and stretched over six years,” she said.

The Tabernacle is an oddity in that it was constructed by bridge builders. “It is built like a wrought-iron bridge,” Ms. Wrenfels said.

The restoration’s first phase that began in 1999 involved structural work and replacing stained glass windows. Very little of the work was visual, as the structure was given a firm foundation it never had before. The Tabernacle now can handle severe winds.

“The second phase was sandblasting and painting of the interior,” Mr. Dagnall said. “Originally it was going to cost $150,000 but it turned out that all that lead-based paint had not been removed in 1979 as was thought. We ended up enveloping the whole building and it cost $600,000.”

So far the Martha’s Vineyard Camp Meeting Association has raised $1.8 million for the renovation, and when all is done the project will likely cost close to $3 million. Contributions have come in every size, from as little as $1 to as big as $500,000 from an anonymous contributor.

Once the cupola is completed, the fourth phase of the overall project involves restoring the upper clerestory. The fifth phase calls for removing the asbestos roof.

To get help to pay for the current part of the project, letters of appeal were mailed out to the Camp Ground property owners and their friends early in December.

The association also has applied to the Oak Bluffs Community Preservation Committee for financial help. The committee has recommended that the town voters put $100,000 toward the project. That vote will take place at next spring’s annual town meeting.

For Mr. Dagnall, the Tabernacle restoration project is more than just paint, steel and building materials.

“The project has done a lot of bringing this community together, more than bringing the residents of 315 houses together,” he said. “The fact is that the Tabernacle has held National Landmark status since 2005.

“I think this project has given a lot to the people,” he said. “It used to be that the Camp Ground was where you got the cheapest cottage on the Island. Today, I think the Tabernacle has been a centerpiece. It has instilled a lot of pride and satisfaction for those involved.”