The U.S. Secret Service and the Navy are strongly urging an unusual zoning change that would limit to 40 feet the height of new buildings in a wide swath of land in Northwest Washington surrounding the Naval Observatory on Massachusetts Avenue.

The proposal, which opponents say raises serious home-rule questions, is rapidly emerging as Washington's latest turf tussle between federal and local interests.

Secret Service officials say that the restrictive height limit is needed to protect the vice president's residence on the grounds of the observatory from potential sniper attack.

The Navy maintains that the tall buildings immediately west of the observatory along fast-growing Wisconsin Avenue are creating havoc with its star- and planet-gazing mission. Astronomers say that faulty celestial readings caused by heat rising from the buildings could affect private and government navigational functions, including the Pentagon's missile guidance systems, satellite tracking and ocean navigation.

The controversial plan already has received the overwhelming, yet nonbinding, support from the National Capital Planning Commission, the federal government's central planning agency in the Washington area. The rezoning request was submitted this week to the D.C. Zoning Commission, which turned the matter over for study to the city's planning department. A report on the proposal is expected in January.

"This has the potential for letting the federal government seize control over local land use," said Christopher Collins, an attorney for a group of developers with plans for an apartment building along a western section of the observatory. Naval and Secret Service officials have criticized the project.

John Tydings, executive vice president of the Greater Washington Board of Trade, said the zoning matter "underscores the need" to better define federal interests in the District.

But backers of the building height rule disagree.

"I'm sympathetic to the interests of the private property owners . . . . But this is the federal city and these kinds of installations need to be protected," said Glen Urquhart, chairman of the NCPC. "This installation was here long before any of the development."

Nearby commercial property owners who risk lower land values if the plan is adopted line up with those who contend that the Navy and Secret Service have overstepped their bounds.

"It practically ruins the value of my property," said Samuel Eisenberg, who has owned Pearson's liquor store at 2436 Wisconsin Ave. NW for 53 years. "I honestly don't believe what {the Navy and Secret Service} are saying is true."

Not all proprietors of the 40 or so small businesses in the area agree.

"We don't want any more big buildings here," said Abdul Hossainkhail, owner of the Grog & Tankard, a Wisconsin Avenue bar. He said the congestion and lack of parking in the area have hurt his business in the last year.

Developers, business executives and some city officials say the new building-height zone could set a dangerous precedent in a city with such a strong federal presence.

Fred Greene, the city's planning director, said the height plan "is too restrictive. It goes a bit beyond what we believe is necessary."

But for local neighborhood activists who are trying to stem the growth of new boxy office towers and high-rise apartment buildings along Wisconsin Avenue, the support of the Navy and Secret Service could not have come at a better time.

"Oh, we love the Navy and Secret Service now," said David Click, a member of the area's Advisory Neighborhood Commission and the Glover Park Citizens Association. "They have a lot more clout than the citizens."

The zoning proposal would restrict to 40 feet, or about three stories, the height of any new office or apartment building in an area up to a quarter-mile from the property line of the 72-acre observatory.

Current zoning in the area allows for a mix of commercial and residential uses. Backers of the rezoning say they included the quiet, residential areas to the north and east of the observatory -- an enclave of expensive homes and embassies -- because they hope to preserve the area from future high-rise development.

Naval and Secret Service officials say they are concerned most, however, with the rapid pace of office and apartment development along Wisconsin Avenue just south of Calvert Street. In that area, building height is now limited to 50 feet, although that level can be exceeded if the city gives a developer a special variance.

Moreover, because of the area's rapidly sloping topography, a building that might be only four or five stories tall fronting on Wisconsin Avenue NW actually can be up to nine stories tall in the rear, an area that abuts the observatory's boundary.

In a move last year that gave impetus to the rezoning plan, a group of local developers proposed constructing a nine-story building in an area about 200 yards from the observatory's tennis court and jogging path frequently used by Vice President Bush.

That plan, still pending before the city's zoning commission, has since been scaled back.

Secret Service officials say the threat to the vice president from the growth in the area surrounding the observatory is genuine. Congress authorized in 1974 that the official residence of the vice president be located on the grounds of the observatory, in part for its seclusion.

"The sniper problem is a very real problem that we are faced with," said Stephen Harrison, deputy assistant director of the agency in recent hearings on the proposal. "The best countermeasure that we think there is is obviously not to allow the potentially dangerous situation to occur in the first place."

He said possible attack could come from snipers who can hit their targets from 1,000 yards away or with rocket fire.

For the Navy, objections to the building frenzy are a little more heavenly. Aside from its role as the nation's master timekeeper, the Naval Observatory also tracks the positions and movements of 40,000 stars.

After mist, fog and an outbreak of malaria forced the observatory from its Foggy Bottom location in 1893, the Navy settled on its present site to observe the stars for navigational purposes.

Over the years, an increasing number of taller buildings close to the telescopes has presented naval observers with a new dilemma: unpredictable light refraction. As it enters the Earth's atmosphere, light is normally bent, a phenomenon astronomers have been able to measure.

But heat rising from tall buildings increases the bending of the light waves, thereby throwing off observations, according to Dr. James Hughes, director of the observatory's astrometry department. And because the level of heat varies with changing weather conditions, observers are unable to account for the bending light.

"There is no doubt the buildings have an effect. We're not raising our objections on a hunch," Hughes said.

Naval officials said they anticipate what will likely be a testy zoning battle.

"The almighty dollar will be hard to combat. Now, if we had our way, we'd say no more development. But we know we'd be severely criticized for that," said Capt. Richard Anawalt, superintendent of the observatory.

Anawalt said moving the navigational viewing operation -- the only one of its kind in the United States -- would mean losing more than 90 years of data the Navy has compiled from the site. He said it would take years to reproduce in another location the precise calculations that are relied upon worldwide by astronomers and military navigational officials.

The area west of the observatory is now mostly a mix of new office and apartment buildings and older, three-story retail shops. But developers have been eyeing the area for years. In fact, in a three-block area along Wisconsin Avenue that is included in the proposed building height zone, nearly two dozen land deals have transpired during the last two years, according to a check of District land records.