There are many considerations to reduce the environmental impact of this project.

Electrical consumption

“Open Air” allows people to control searchlights that use 240kW of power in total. While 240kW is a very substantial electrical consumption, for perspective, the entire month-long project uses less power than a single football game.

The power is all supplied by quiet generators which run on more than 50% renewable biodiesel. In addition, a carbon offset plan is in place with the Nature Conservancy www.nature.org to reduce the project’s carbon footprint to zero.

Light pollution

The lights are tightly focused so that all the power is concentrated into narrow beams that are never pointed towards neighbouring buildings, flight paths or sensitive ecological areas. The lateral light pollution generated by the beams is much smaller than any street light, advertisement or corporate logo found on any of Philadelphia’s buildings. Contrary to lasers which concentrate light in a perfectly parallel beam, our lights do diverge with distance and lose intensity by the square of their target’s distance.

Our team of technicians, surveyors, park board officials and civil engineers have measured the exact position and orientation of each searchlight and built accurate 3D models of the surrounding buildings; our control system is programmed to prevent searchlights to be aimed towards the buildings.

Sound pollution

The project is completely silent, there is no sound or music. The voices can be heard through the mobile app, the web site or two small speakers placed on Eakins Oval and Logan Square, but the sound can only be heard right beside them.

Bird migration

The project has been developed in close consultation with Audubon Pennsylvania and partner organizations in a collaborative effort to minimize and mitigate any effect of the project on migratory birds. The considerations are as follows:

  1. The project incorporates automatic, periodic, total “black-out” periods within the show to lessen the possibility that that birds become “trapped”.
  1. By design the lights are never stationed in one position, which diminishes situations where the birds might get stuck. On the other hand, the lights scan slowly so as to not startle the birds.
  1. The beams are kept away from any and all tall buildings in an effort to avoid attracting birds toward actual physical structures that they could collide into.
  1. The intensity of the beams is constantly modulated according to the live voice analysis. This means that the total average luminous output of the project is considerably less than all previous Lozano-Hemmer searchlight projects.
  1. We have a full-time monitoring plan in place, a mixture of personnel (ornithologists, technicians, Audubon volunteers) and technology (doppler radar, binoculars, sound recorders. The monitoring team has a master telephone number for the technicians on site to shut down the lights immediately.
  1. The searchlights have a severe UV cut filter glass, as birds can see ultraviolet light.
  1. In addition to the above, Dr. J. Alan Clark, professor at the Dept of Biological Sciences of Fordham University, has conducted an independent scientific study using the project’s lights to test the effect of different light color filters on the migratory pattern of birds. His results should be published when he analyses all the data collected.

Previous exhibitions of similar Lozano-Hemmer projects with interactive searchlights have been successfully staged in many cities all over the world. In the small Japanese city of Yamaguchi his work “Amodal Suspension” co-existed with the bird sanctuary that was in the neighbouring hill and which was completely undisturbed. In the city of Toronto, for his work “Pulse Front”, the searchlights were 250 m away from city airport on one side and 100 m away from residential towers on the other. For “Vectorial Elevation” in the Vancouver Olympics, the project was successfully sited for six weeks in English Bay, an ecologically sensitive area home to bald eagles, woodpeckers, herons, jays, ospreys, tanagers, finches and other species.

Dark skies

Lozano-Hemmer writes:

“As someone involved in amateur astronomy, who has worked with NASA on two projects, and most importantly, as someone humbled and inspired by the majesty of a starry sky, for me light pollution is a serious issue and I am aware of the inconvenience that the project will cause.

However, this project is designed to be an ephemeral installation in an urban setting: it is in Philadelphia only for a few weeks, during two of the largest festivals in the city. We have been negotiating for the city to turn off sodium lighting in the Parkway to lessen our net impact. For opening night, lights were turned off between 21st street and Eakins Oval, creating the darkest night in the 75 years that the Parkway has been artificially illuminated. For the record, I only advocate using searchlights if the project is short-lived, if it takes place in an urban center where there is already substantial light pollution, if ample consultation is undertaken with wildlife experts and if it is associated to a festival, memorial or other public special event.

It is my belief that the greatest contribution towards achieving dark skies will be lobbying for the change of permanent lighting fixtures, advertisements, “architainment” installations and urban screens, not short-term projects. For what it is worth, I like to think of my work as being within the long tradition of “Sky Art” (e.g. Otto Piene, Roger Malina, Rockne Krebs, etc), which seeks to direct attention to the sky and space to ask questions about our own place in the world. In that vein, my previous interactive searchlight project “Amodal Suspension” was opened by a live message coming from the International Space Station by Astronaut Pedro Duque and from Earth by Astronaut Mamoru Mohri.

During a few weeks my piece will indeed illuminate Philadelphia’s dark sky, —though a walk in the city at night will confirm that unfortunately there is no such thing—, but hopefully will give millions of people something beautiful to look at during the Live Arts and Design Philadelphia Festivals, connecting the city to people world-wide and activating neighbourhoods that need more pedestrians at night for fostering community, safety and participation.”

Open Air has teamed up with the Franklin Institute to develop a Planetarium on the Parkway a free event featuring Chief Astronomer Derrick Pitts on Oct 12 at 8:30PM. In this dynamic presentation, a custom-made interface has been developed for Dr. Pitts to point at salient astral objects using the searchlights, something which should lessen the parallax problems that are typical of outdoor presentations. Everyone is welcome, join us at Eakins Oval, 24th and the Parkway!

Merlin Radar
Bill Stripling/courtesy National Audubon Society
Bill Stripling/courtesy National Audubon Society
Bill Stripling/courtesy National Audubon Society
Bill Stripling/courtesy National Audubon Society
Flyways Map - Credits Audubon

Audubon Pennsylvania and the Macaulay Library of Natural Sounds and Video at Cornell University have submitted dozens of bird calls to the Open Air Archive, so that they can control the lights. You can listen to these birds here.

Philadelphia is on the Atlantic Flyway, a major avian migratory route that encompasses some of the hemisphere’s most productive ecosystems, including forests, beaches, and coastal wetlands. From the northern Atlantic Coast and through the Caribbean to South America, Audubon is working to support this avian superhighway’s 500-plus bird species and millions of individual birds. With only one-tenth of the U.S. landmass, this flyway is home to one-third of the nation’s people. And dense population carries with it many challenges for birds and habitat: development and sprawl, incompatible agriculture, overfishing, and climate change.

Forty percent of the Atlantic Flyway’s bird species are species of conservation need. These include the Wood Thrush, whose population has been reduced by half in the past 40 years. Without protected, welcoming stopover habitat, even the hardiest Atlantic Flyway migrants are hard pressed to complete their spring and fall journeys. The Important Bird Areas Program (IBA) is a global effort to identify and conserve areas that are vital to birds and other biodiversity. The U.S. section of the Atlantic Flyway, stretching from Maine down to Florida, is home to 139 global Important Bird Areas. Fairmount Park in Philadlephia is one of these Important Bird Areas.

Link to ways you can help birds during their fall migration