|
Jan. 28, 2004
Effect of Skyglow on Star Visibility
Quantifying the Effect of Skyglow on the Visibility of Stars
Jacob Rucker, 13, Del Mar, Calif.
Discovery Kids "TV Star" Award, Discovery Channel Young Scientist Challenge, 2003
Project background: Skyglow, caused by excess light from urban centers, reduces the visibility of stars and is an increasing problem for astronomical observations. Jacob lives in the San Diego area, where the climate is dry, the skies are clear, and mountains loom nearby—ideal conditions for night-sky observations. However, light pollution in this area hampers visibility at the Palomar Observatory and Mt. Laguna Observatory. Jacob wanted to test whether it was possible to predict the impact of skyglow based on a site's distance from an urban center.
Tactics and results: From sites 30, 60, 75, and 124 kilometers from the urban center of San Diego County, Jacob took 120 photographs of the zenith on nights of similar weather and moonlight conditions between August 2002 and January 2003. He developed and scanned the photos, turning them into more than 500 bitmap files. Then, he wrote a computer program to convert the bitmap files into pixel arrays, with pixel intensity values ranging from 0 to 765, and to determine the number of pixels at each intensity level. He used the intensity intervals for each site to find the change in intensity (brightness) as a function of a site’s distance from the urban center.
Using the formula he developed, Jacob found that the observable, visible light from stars remains below 50 percent until about 35 kilometers from a city the size of San Diego. The visibility does not improve to 90 percent until you reach a distance of 70 kilometers away from the city. Thus, skyglow is a serious threat to astronomical observations at Mt. Laguna Observatory (45 miles from San Diego) and Palomar Observatory (40 miles from San Diego).
Read the latest science fair news
Get a science fair tip
Browse a list of science fair topics
Talk Back:
Do you have any comments about this ScienceFairZone? Send them
to us using the form below.
|
SNK RSS Feed 
