Interdisciplinary Qualifying Project: Dark Sky


Summer 2013 - Bar Harbor, Maine
Advisor: Dr. Fred Bianchi
Team: A. Larsen, J. Morse, M. Rolón, S. Roth

Abstract
The purpose of this project was to map the quality of the night sky on Mount Desert Island and Schoodic Peninsula for the National Park Service. The first phase of the project was acquiring data points from across the island using a Sky Quality Meter. The second involved mapping the data using Geographic Information System software. The results of this project can be used by Acadia National Park to advise new lighting ordinance policies within the park and in major towns on Mount Desert Island.
Sky Quality meter collecting data at Sand Beach
Illustrating differences between ecological and astronomical light pollution (Longcore)




Executive Summary


Synthetic lighting is often seen as an advance in technology and an improvement in the quality of life. Yet the use of excessive lighting is detrimental to the local environment. Large urban areas and cities emanate a vast amount of light during the night, causing sky glow. This in turn covers the dark sky and hides the view of stars, planets, and the Milky Way.

The Dark Sky Project’s goal is to prevent sky glow from covering the skies of Mount Desert Island and Acadia National Park; one of the few locations left in the Northeast to still have a clear view of the sky.

The Dark Sky Project is a response to the National Park Service’s Call to Action. Under the sponsorship of Acadia National Park, the team focused on point 27, “Starry, Starry Night.” The point focuses on natural darkness, classifying it as a natural resource. It calls for the preservation of a natural dark sky, in an effort to restrain man-made light from intruding on such.

College of the Atlantic (CoA) and the Astronomy Institute of Maine are the only studies done on light levels on Mount Desert. In the winter of 2006/2007, two students from the CoA created a color-scale map representing the different light levels across the island using Sky Quality Meters (SQMs). The Astronomy Institute of Maine, on the other hand, used special CCD cameras and created gradient pictures of specific locations throughout the island. The Dark Sky Project based their study off of the CoA study.

There are three reasons for synthetic lighting: general illumination, security, and decorative. Light pollution is created from excessive use of this lighting. The three types of light pollution are upward light, light trespass, and source intensity. Light pollution has detrimental effects on the ecology of an area. The physiology of humans can be affected.

Many animals are affected from excess lighting by disturbing their circadian clock. Light pollution can have several effects on humans and even be a promoter of cancer.

Following a specific calendar, the Dark Sky Project executed their study over seven weeks, starting mid June through the end of July 2013. The first steps were to assess possible locations to take readings and to test the equipment. Certain criteria had to be met in order for the locations to be valid. Key aspects such as tree coverage, weather, and the lunar calendar were closely monitored in order to get consistent readings.

The most important piece of equipment used was the Sky Quality Meter Lens USB Data Logger (SQM-LU-DL). The device is used to collect light readings of the sky, measured in magnitudes per square arcsecond. Using the meter and a Global Positioning System (GPS) device, the team was able to collect the raw data across the island.

After the collection of raw data, the next step was the creation of maps using Geographic Information System (GIS) software. Using the GPS coordinates and the SQM readings, the software can use interpolation to generate a color-coded map.

The Bortle scale is widely accepted by astronomers as a way to assess the quality of a night sky. Ranging from 1 to 9, the Bortle scale classifies different night skies from darkest to brightest respectively.

The collection of data was carried out by driving along main roads, secondary roads, and some fire roads, and taking measurements along the way. The team made sure to stop every half-mile, or as often as possible if tree coverage was too dense for proper readings.

The team was able to create various maps to represent light levels on the island. In order to compare the new results to the CoA study, the first map created used the same color scale. This proved to give a low quality representation of the data, so the team used the Bortle scale to illustrate their final results. Finally, the team created modified versions of the map. For example, a map was made marking the park boundaries.

Final analysis compares the CoA study to the WPI study. It describes the benefits from using the Bortle scale over the CoA’s scale, and finally discusses certain points of interest on the island.

An important factor was the different SQMs used by the two studies. The difference in lens width was the most important difference between the two studies. Another inconsistency was the season each study was conducted. The CoA study was done during the winter, while the WPI study was done during the summer.

The reasoning behind using the Bortle scale is simple. Since astronomers and stargazers commonly use the scale, the color scheme is easily identified and understood. Additionally, the Bortle scale gave a more comprehensive representation of the data collected by the WPI team.

The team analyzed specific points of interest on the island. Bar Harbor, Northeast Harbor, Southwest Harbor, and the Somesville area were analyzed because of bright light emissions. Seawall and Sand Beach were analyzed because of their dark readings.

Finally, the team explains recommendations for future studies. Continuation of the project during the summer would be ideal in order to start a longitudinal study. Expansion to other seasons to have a comparison between different times of the year was recommended. Additional studies were recommended. A more thorough study on Schoodic Peninsula and time-lapse studies on different parts of the island were suggested.

The Dark Sky Project team met the goals they set. The collection of data and creation of maps was successful. A baseline for future studies on Mount Desert Island was created.
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The work displayed here is by Andrew Larsen unless otherwise credited.