County sets hearings on proposal to reduce light around Turner Farm Observatory

Fairfax County is exploring ways to preserve dark skies around Turner Farm Park Observatory in Great Falls.

At a Tuesday (Sept. 12) meeting, the Fairfax County Board of Supervisors announced public hearings on a proposed regulation that would limit outdoor lighting within a half-mile of the observatory at 925 Springvale Road.

A hearing before the Fairfax County Planning Commission is set for Oct. 18, followed by a Board of Supervisors’ meeting on Nov. 21.

If approved, the amendment would apply to 525 lots near the observatory.

The Fairfax County Police Department “has advised that proper lighting can be a deterrent for criminal activity, but over-lighting is not needed to facilitate a safe environment,” according to a staff report in the board agenda.

Staff say light pollution interferes significantly with the ability to complete astronomical observations at the observatory. For example, a single light bulb located one half-mile from the observatory has the same impact as four bulbs one mile away or almost 200 bulbs in Tysons, which is roughly seven miles away.

According to the draft proposal, motion-activated lights must be 1,500 lumens or less — a drop from the current limit of 4,000 lumens or less. Additionally, all lights need to be fully cut off, which is currently not required.

Still, an exception will remain allowing lights at a door or a garage of up to 1,500 lumens per fixture.

The regulation would also set limits on the number of up lights or spotlights allowed. Currently, any number are allowed as long as they are fully cut off or shielded to confine light. The changes would limit each fixture to 300 lumens.

The draft text was developed after several town halls and an online community survey. The scope of the proposal was changed after discussions with stakeholders.

For example, the current version lets legally existing lights remain until replaced, superseding a previous version that required existing lights to comply within five years of the policy’s implementation.

In a statement to FFXnow, a Great Falls Citizens Association representative said the introduction of the proposal represents a milestone after eight years of works.

“This has special significance for the Turner Farm, where the Fairfax County Park Authority made a major investment in a roll-top astronomy building,” GFCA said in a statement. “If adopted, the proposed amendment will affect the brightness of future outdoor lighting of homes within a one-half mile radius of the county’s observatory.”

GFCA also acknowledged that, while not all residents in the affected area will agree with the county’s plans, county staff made “significant changes in the proposed requirements.”

“GFCA believes that the amendment offers reasonable measures to address concerns while preserving dark skies near the observatory,” the association said.