Dark sky lighting

What is Dark Sky Lighting?

Provide adequate outdoor lighting to see and feel secure while avoiding sky glow, glare and light trespass.


We are ready to help you determine the type and location of your outdoor lighting fixtures, understand and comply with dark sky lighting ordinances, and utilize the latest energy saving technologies. Architectural Lighting Design Services. More lighting questions answered on our FAQ page.


Model Lighting Ordinance - Download PDF June 2011

Illuminating Engineering Society of North America (IES) and International Dark Sky Association (IDA) jointly created the Model Lighting Ordinance (MOL) including this BUG Diagram and Zones Chart included below.


BUG Diagram - Backlight - Uplight - Glare




Key: UH=Uplight High, UL=Uplight Low, BVH=Backlight Very High, BH=Backlight High, BM=Backlight Medium, BL=Backlight Low, FVH=Forward Light Very High, FH=Forward Light High, FM=Forward Light Medium, FL=Forward Light Low.


The BUG, Backlight, Uplight, and Glare, ratings may be used to evaluate luminaire optical performance related to light trespass, sky glow, and high angle brightness control. These ratings are based on a zonal lumen calculations from photometric testing procedures approved by the Illuminating Engineering Society for outdoor luminaries (LM-31 or LM-35).

BUG typically cannot be used for residential luminaires unless they have been photometrically tested. For non-photometrically tested residential luminaires, shielding description is used instead.


Luminaire Shielding Designs

Image courtesy of Bob Crelin

          Fully Shielded Luminaires

North America at Night

Courtesy - National Geophysical Data Center, Boulder, Colorado - NOAA - National Oceanic and Atmospheric Administration

Include Dark Sky Lighting techniques to save energy and to see our stars.


Dark Sky Checklist


  • Safety and Security
  • Light Trespass
  • Light Pollution
  • Star Gazing
  • Dark Night's Sleep
  • Neighbor Friendly
  • Eye Adaptation
  • Preserving Natural Views
  • Environmental Sensitivity
  • Viewing Angles
  • Direct Glare
  • Reflected Glare
  • Reflected Light
  • Luminaire Optics
  • Luminaire Shielding
  • Light Distribution and Aiming Angles
  • Light Level
  • Fixture Brightness
  • Fixture Height
  • Fixture Spacing
  • Fixture Density
  • Light Uniformity
  • Efficiency – Light Source Lumens Per Watt
  • Efficacy – How Much Light Gets Out of Fixture
  • Color Temperature of the Source - CRI
  • Spill Light From Inside Buildings
  • Controls - Fixture Grouping
  • Daylight Sensors
  • Motion Detectors
  • Digital Timers
  • Mechanical Timers
  • Astronomical Clock Timers
  • Curfew Lighting Reductions
  • Building Codes
  • Initial Lumen Allowance
  • Outdoor Lighting Ordinances
  • Outdoor Lighting Zones
  • BUG - Backlight, Uplight, Glare



Model Lighting Ordinance - 2011 PDF

Includes Definations




Outdoor Lighting Guide - 1977 PDF

By Trish Odenthal



Nighttime Lights of the World

The POET Program - Protect Our Environmental Treasures - designed specifically for middle and high school teachers to use in their classes - PDF.




MOL - Lighting Zones

Zone Recommended Uses or Areas Zoning Considerations
LZ-0 Lighting Zone 0 should be applied to areas in which permanent lighting is not expected and when used, is limited in the amount of lighting and the period of operation. LZ-0 typically includes undeveloped areas of open space, wilderness parks and preserves, areas near astronomical observatories, or any other area where the protection of a dark environment is critical. Special review should be required for any permanent lighting in this zone. Some rural communities may choose to adopt LZ-0 for residential areas.

Recommended default zone for wilderness areas, parks and preserves, and undeveloped rural areas.
Includes protected wildlife areas and corridors.

LZ-1 Lighting Zone 1 pertains to areas that desire low ambient lighting levels. These typically
include single and two family residential communities, rural town centers, business parks, and other commercial or industrial / storage areas typically with limited nighttime activity. May also include the developed areas in parks and other natural settings.

Recommended default zone for rural and low density residential areas.
Includes residential single or two family; agricultural zone districts; rural residential
zone districts; business parks; open space include preserves in developed areas.

LZ-2 Lighting Zone 2 pertains to areas with moderate ambient lighting levels. These typically
include multifamily residential uses, institutional residential uses, schools, churches, hospitals, hotels/motels, commercial and/or businesses areas with evening activities embedded in predominately residential areas, neighborhood serving recreational and playing fields and/or mixed use development with a predominance of residential uses. Can be used to accommodate a district of outdoor sales or industry in an area otherwise zoned LZ-1.

Recommended default zone for light commercial business districts and high density or mixed use residential districts.
Includes neighborhood business districts; churches, schools and neighborhood recreation facilities; and light industrial zoning with modest nighttime uses or lighting requirements.

LZ-3 Lighting Zone 3 pertains to areas with moderately high lighting levels. These typically include commercial corridors, high intensitysuburban commercial areas, town centers, mixed use areas, industrial uses and shipping and rail yards with high night time activity, high use recreational and playing fields, regional shopping malls, car dealerships, gas stations, and other nighttime active exterior retail areas.

Recommended default zone for large cities' business district.
Includes business zone districts; commercial mixed use; and heavy industrial and/or manufacturing zone districts.

LZ-4 Lighting zone 4 pertains to areas of very high ambient lighting levels. LZ-4 should only be
used for special cases and is not appropriate for most cities. LZ-4 may be used for
extremely unusual installations such as high density entertainment districts, and heavy industrial uses.

Not a default zone.

Includes high intensity business or industrial zone districts.