Planning
& Zoning Commission
c/o Mr.
John Neunuebel
Planning
Director
Town of
850
Dear
Commissioners:
We
respectfully request that the Planning and Zoning Commission of the Town of
Please
recall that the Observatory supported the proposal to double the amount of
light permitted under the Sahuarita OLC just a few months ago as a compromise
for uniformity and ease of compliance.
The developers now have the same lumens cap as the surrounding county
land. To ask for another doubling seems
unreasonable.
We take
exception to the applicant’s statement, “More importantly, the total number of
lumens does not have an adverse effect on the Mount Hopkins Observatory’s light
gathering capabilities due to the use of full-cutoff low pressure sodium
fixtures.”
Light in
the night sky harms astronomy in two ways:
Light, from whatever source (including LPS), escaping into the night sky
overwhelms the light of stars and other fainter sources, making them hard or
impossible to measure at all. In
addition, astronomers who study the individual colors of star light find the
colors of Metal Halide, High Pressure Sodium and LPS lamp-light overlaying and
hiding the star light colors. LPS is the
least harmful because it only has one color, but it is not harmless.
The total
number of lumens has a tremendous effect.
From even the best outdoor lighting systems, an average of 15% of the
light reflects off of the ground and into the night sky. So any increase in lighting directly
increases the amount of light in the sky.
The
applicant expresses concern about criminal activity and liability resulting
from following the current Code. The
City of
We are
concerned about the precedent that would be set by granting this variance. Diamond Ventures has assured us that this would
not be precedent-setting since the Town would individually review every such
application, yet they cite the precedents of the light levels of other
commercial installations in their own application. (These other installations were not built
under the present code and don’t seem relevant.)
Hyman
Kaplan, Chair of the Pima County Outdoor Lighting Code Committee, has commented
on the design aspects of the application.
From his remarks, it seems the technical arguments for a variance are
wanting. The lighting allowances under
the Sahuarita Code meet or exceed the Illuminating Engineering Society
recommendations in a properly designed application.
Please
remember that the Outdoor Lighting Code is not only for the benefit of
astronomical science. It encourages good
lighting practice to save energy, prevent light trespass, and provide safe use
of the night.
Thank you.
Sincerely,
Dan
Brocious
Public
Information
Whipple
Observatory
Encl./1
maderavar1.doc