Nantucket commission weighs dark‑sky streetlight pilots, compliance deadline for town fixtures

Gail Walker, president of Nantucket Lights, told the Nantucket Historical Commission on April 18 that the town’s new outdoor‑lighting bylaw (Chapter 102) — adopted after a 2023 citizen warrant article — requires decorative street lights to meet stricter controls, and that all town‑owned decorative fixtures must be brought into compliance by Jan. 1, 2029.

Walker said the bylaw requires fixtures with more than 600 lumens to be fully shielded, limits color temperature to 2,700 Kelvin or less, caps lumen output, and restricts when lights must be turned off. She emphasized the bylaw’s “bug” rating standard for decorative fixtures (the bylaw caps uplighting at U=0 for these fixtures) and urged the commission to consider dark‑sky globeless options that eliminate uplighting.

The commission viewed a piloted globeless Victorian‑style fixture that was installed on Main Street as a loaned demonstration model and discussed three design options from the manufacturer intended to make a globeless fixture look more historical. Walker said a Worcester Polytechnic Institute student survey of the pilot drew 56 responses (about 50% year‑round residents, 13% seasonal residents, 38% tourists) and that 63% of respondents supported the globeless pilot after its benefits were explained.

Commissioners and members of the public raised both historic‑preservation and safety questions. Commissioner Clement Derkeis said the globe “makes a huge difference” visually but agreed that globes add glare; he supported removing the globe and suggested a matte black cap to reduce upward reflection. Commissioner Angus and others said adding modest internal detailing — a small internal glass element or “guts” to suggest the historic light source — might make a globeless fixture feel less visually jarring without violating the U=0 uplighting requirement. Several commissioners noted LEDs can be dimmed per fixture and that per‑fixture photometric testing could produce lighting levels on sidewalks equal to or better than older fixtures while eliminating uplight.

Mary Bergman of the Nantucket Preservation Trust urged broader public outreach, saying the change to Main Street’s appearance will evoke strong reactions and recommending broader surveying this summer when more visitors are present. Walker said she is pursuing a possible exception from Dark Sky International for Main Street globes but cautioned that adding a globe would raise the fixture’s uplight rating (to U=2 in the pilot case) and could conflict with the bylaw and Nantucket’s pursuit of dark‑sky community certification. She said the manufacturer will perform lab photometrics if the commission asks them to build and test a variant.

Commissioners requested more direct engagement with manufacturers and DPW before the commission gives formal guidance: representatives offered to appear at the commission’s May meeting and to meet individually with commissioners to walk the downtown lights and show sketches. Commissioners also suggested targeted summer outreach (QR or in‑person surveys) to gather wider public input before procurement. Walker said DPW wants to comply with the bylaw but seeks the commission’s guidance to avoid local backlash and to inform procurement and installation schedules.

The discussion also covered privately owned globeless fixtures already on the island, the tradeoffs between Victorian and colonial fixture styles, and the broader goal of using town fixtures to lead by example so private owners will follow.

The conversation concluded with agreement to continue the topic at the commission’s May meeting and to consider inviting manufacturer representatives for a direct briefing and lab results when available.