On a clear night on the Vineyard at this time of year, look skyward and you can see the Milky Way. The Island is one of the few places left on the East Coast where the galaxy can still be seen with clarity. But even here, where the dark night sky is considered a precious resource, like the clear ocean water and unpolluted landscape, there is growing concern about the strains being put on that resource from residential development.

Large houses with their outdoor floodlights, lit outdoor pools, walls of glass and skylights are being called cumulative culprits in the fight to keep the night sky dark.

“One of the unique things about this Island is how dark it is, and it is getting less dark because of increased lighting,” said Suzan Bellincampi, executive director of the Felix Neck Wildlife Sanctuary. “The hue you get off a city with this foggy, eerie weird light at night, that’s a major source of light pollution. But what’s happening here is more like we’re chipping at an ice block. Little by little, every new house and increased outside lighting, we’re adding little bits and making the problem bigger,” she said. “You might ask, does one light really matter? But when you’re talking about thousands of houses, it adds up.”

Light pollution and the lesser-known legal term of light trespass are now terms under discussion at planning and zoning meetings on the Vineyard and beyond. A bill to create a law to protect the dark night sky throughout the commonwealth has been introduced but never passed in the Massachusetts legislature.

All six Vineyard towns regulate light pollution and light trespass either through zoning bylaws or lighting standards. The three up-Island towns have adopted bylaws to ensure “the unique quality of the night sky.” Lighting standards in Edgartown, Oak Bluffs and Tisbury are included in other town bylaws.

— Mark Alan Lovewell

Chilmark, West Tisbury and Aquinnah all require outdoor light fixtures to be shielded and pointed downward to prevent spillage and glare into the sky or beyond property lines. Outdoor lamps may not be higher than the eaves of structures.

Aquinnah has the strictest bylaw, adopted in 1999 under its townwide district of critical planning concern. Intended to “preserve the rural character of the town, promote the habitat of nocturnal wildlife, prevent light pollution, preserve and enhance the character of nighttime views and to be considerate to neighbors,” the bylaw limits outdoor lightbulbs to soft white, red or yellow whenever possible. The town also restricts walls of glass in residential homes and strongly discourages skylights.

“Part of the problem is you can’t control interior lighting in a house and yet people can do things that will throw a lot of light out at night,” said planning board chairman Peter Temple.

Mr. Temple said he receives complaints about light pollution regularly. The other day he received a call complaining about the glow from a soda machine at the cliffs and the light emitted from the ATM.

“It’s very visible to neighbors,” he said.

In Chilmark, the lighting bylaw, the first one adopted on the Island in 1998, is also written to maintain rural character in the town. A similar bylaw was later adopted in West Tisbury.

The bylaws include specific language about diminishing light spillage from indoor sources, minimizing light trespass, decreasing light pollution and preventing “unreasonable interference with astronomical observations.”

Bug zappers are prohibited.

Chilmark and Edgartown building inspector Leonard Jason Jr. said he rarely receives complaints about light pollution. He said he had a complaint from someone in Aquinnah about a house they could see across Menemsha Pond, and most recently a complaint about the Adam Zoia house on Nashaquitsa Pond, where the abutters are claiming light trespass.

But he did not deny that light pollution is an increasing area of concern. “When I was a kid we fought over street lights at the annual town meeting in Chilmark whether or not to have them,” Mr. Jason said. “Now we’ve got lights everywhere.”

In Edgartown, he recalled past complaints about the Harbor View Hotel’s windows and the well-known issue over Ernie Boch’s property with its extra-brilliant exterior lighting scheme on the Edgartown harbor.

“Clearly there’s a newfound appreciation for dark skies at night and what it means when it’s lost,” said Vineyard Conservation Society executive director Brendan O’Neill. “We’re beginning to see more complex outdoor landscape lighting . . . that calls for things like floodlights on rhododendrons.”

The Martha’s Vineyard Commission is also acutely aware of light pollution hazards and imposes conditions on developments to restrict and regulate outdoor lighting, MVC planner Paul Foley said. When the Martha’s Vineyard Hospital applied for a new parking lot in 2009, MVC conditions required the hospital to plant trees around the edges so car lights would not spill into neighboring houses. The lights were also required to be bollards instead of regular streetlights.

On Nantucket, similar initiatives have been under way to control light pollution, but to little avail, said Janet Schulte, director of the Mariah Mitchell Observatory. An islandwide ordinance was passed in 2005 to regulate outdoor lighting, but she said enforcement has been lax. On August 20 the observatory will host a public forum on the issue.

“There is more light in our lives where it’s not supposed to be . . . and we don’t have the clarity that you used to have,” Ms. Schulte said. “There are places on the island where you can see the Milky Way, and if you go a mile you can’t see it anymore. For Nantucketers, part of the experience of being here is dark sky. It’s the darkest place on the East Coast and we don’t want to lose that as a unique experience.”

On Beacon Hill, efforts to enact statewide legislation for an outdoor lighting bill have stalled for the past 10 years. The act Improving Outdoor Lighting and Increasing Dark Sky Visibility was conceived to help towns lower energy costs and increase safety by regulating lighting practices statewide. To date, 18 states have outdoor lighting regulations.

The bill would require state and town-funded projects to use fully-shielded exterior lighting in new or replacement buildings.

The primary sponsors of the bill are the New England Light Pollution Advisory Group and the International Dark-Sky Association.

“Rather than a patchwork approach . . . we’re trying to create legislation that has a very common-sense approach,” said Kelly Beaty, a board member of the dark sky association and a Massachusetts resident. “Ninety-nine per cent of all Americans have some degree of light pollution in their sky, two-thirds of those can’t see the Milky Way,” he continued. “Those towns that want to preserve the quality of life they have are most likely to pass ordinances . . . but the big cities, those are the biggest violators. Cities need a comprehensive kind of solution.”

Mr. Beaty said the bill faces opposition from the National Electrical Manufacturers Association. Backers plan to reintroduce it in the next legislative session.

He called light pollution a worldwide problem.

“Not only have we crept deeper and later into activities . . . but we’ve also decided that we’re going to light everything up so we can make our way around while we’re out late at night,” Mr. Beaty said.

“We have a mantra in the light pollution fight which is to use only the light you need where you need it and when you need it. Anything else is a waste. It’s common sense but a lot of it is applied in everyday life.”