Hundredfold Farm Cohousing Community

"a place to grow"

Hundredfold Farm Cohousing, Gettysburg, Pennsylvania

Hundredfold Farm Light Pollution Guidelines

The beauty of the night sky is recognized as a valuable natural asset of the Hundredfold Farm community. As a community, we agree that a good night lighting policy strikes a balance between a number of important considerations, including but not limited to:

  • Ability to stargaze
  • Affordability
  • Energy conservation
  • Hospitality
  • Safety

The ability to stargaze has been valued and exercised prior to groundbreaking at Hundredfold Farm. Subsequent development should be considerate of the stargazer, preserving the ability to view the night sky. Two impacts should be considered in any lighting condition: the sky and the eye. Effort and money should be expended to avoid upwardly- or horizontally-directed light. Light that is directed upward has a negative impact on the ability of people to stargaze at Hundredfold Farm and in the surrounding area. Light that is directed horizontally impacts the stargazer's eyes, making it difficult to adjust eye sensitivity to be able to see dim objects in the night sky. "Full-cutoff shielded" lighting prevents a person at a distance from seeing the direct glare of a bulb. Also, alternative wavelength lighting exists that is easier on the eye. Care should be taken to reduce the amount of light from residence windows (e.g. no thin drapes). Care should also be taken with other horizontally-directed lights such as flashlights or car headlights. For example, we may wish to landscape so as to minimize the amount of light escaping from the parking lot.

As part of our shared value of sustainable living, we wish to conserve lighting energy. Energy-efficient lighting should be used when possible. There are three dimensions to the energy efficiency of lighting. First, the light source should produce adequate light efficiently, maximizing lumens and minimizing heat loss. Second, the light produced should be focused and aimed where needed. The purpose of each light source should be considered in the choice of shielding and shape of reflective components behind the bulb. Third, a light source should function at the times when needed. Timers and motion sensors can help in minimizing lighting at unnecessary times.

The development of Hundredfold Farm itself is an expression of the value of community at many levels. We believe that the resources of this land will be best preserved by a modest and environmentally sound development, as opposed to our doing no development at all. The needs of the community will necessarily be in tension with preservation of the land, but we hope to establish a sustainable equilibrium. A guest to Hundredfold Farm should have adequate lighting to comfortably and safely park and find a way to any home at night. Special care should be taken to consider not only the safety of the resident, but also the safety of the nighttime visitor who is unfamiliar with the layout of the community. For example, motion-sensitive, energy-efficient, shielded path lighting would only be part of a solution. The visitor must easily gain an understanding of the community layout without excessive lighting. One possible solution would be to have motion sensitive lighting by maps located in parking lots.

In considering any possible lighting plan, one should consider all perspectives: the community member paying for lighting-related expenses, the stargazer atop the hill, the guest we wish to welcome in from the dark, and the many to whom we hope to teach energy conservancy by example. May we find a wise balance.

Online resources:

(Adopted 05/31/03 )