1. Introduction to Outdoor Lighting
And How it Affects Light Pollution
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Dark Skies Awareness
2. Scope of Lesson
• We will discuss the history of
outdoor lighting
• Its purpose
• Types of Lamps
• Fundamentals of Design
• Why too much light at night is
harmful
• Activities to demonstrate good
lighting.
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Dark Skies Awareness
4. Define Nightscape
• For many centuries the
nightscape was the moon and
stars. During a full moon it
would be relatively bright and
during a new moon, rather
dark.
• For urban dwellers over the
last 100 years it has come to
be described as lighting
buildings, streets, and open
spaces.
• Could there be a compromise?
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Dark Skies Awareness
5. History
• Street lighting as we know it began
approximately 300 years ago.
• These were oil lamps placed on wooden
poles
• By the early 18th century oil lamps were
still used but the poles and lamps were
made of cast-iron fixtures.
• The beginning of the 19th saw gas lamps
come into use.
• By the 20th century electric lamps were
in wide use.
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Dark Skies Awareness
6. What is outdoor lighting now?
• Street lighting
• Roadway lighting
• Parks
• Stadiums
• Parking lots
• Landscaping
• Residential
• Buildings
• Pedestrian and Bicycling Pathways
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Dark Skies Awareness
7. Purpose of outdoor lighting
• Provide a safe and secure
environment at night.
• Extend the use of parks
and walkways into the
night.
• To enhance
historic/notable features
• To enhance travel on the
roads and at intersections.
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Dark Skies Awareness
8. What is light pollution?
• It is wasted light that performs no function or task
– Such as sky glow
– Glare
• It is artificial light that goes where it’s not supposed to go
– Neighbor’s window
– Into the sky
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Dark Skies Awareness
10. Outdoor lighting should…
• Enhance visibility, not
impede it
• Not produce glare
• Be a part of the total
nightscape, not all of it
• Not allow light trespass on
other’s property
• Have a master plan
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Dark Skies Awareness
11. Outdoor lighting should…
• Provide a safe and secure environment
• Create safe routes for traffic, cyclists and
pedestrians
• Facilitate the extended use of outdoor spaces
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Dark Skies Awareness
13. Importance of Shielding Light
• Unshielded lights produce
– Sky Glow
– Glare
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Dark Skies Awareness
14. The Issues
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Dark Skies Awareness
15. Unshielded Luminaires Waste Energy
• Light that spills out, away from the task it needs to be used
for is wasted energy, and wasted money.
• Environmentally responsible outdoor lighting reduces this
waste and costs no more than earlier manufactured light
fixtures.
• Below- the Escondido Education Center before on the left
and after on the right. Unnecessary lights on the roof only
added to their light bill, not to the safety of the parking lot.
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Dark Skies Awareness
16. Non-shielded lights are unsafe
• The glaring lamp to the right of the path was installed to protect students
at night.
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Dark Skies Awareness
17. Where did the student go?
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Dark Skies Awareness
18. Negative Impact on Wildlife
• Animals and plants live by a
rhythm based on a 24 hour
cycle. Wildlife and fish can
become disoriented by too
much artificial light at night.
• It interferes with migration,
mating, foraging for food, and
sleep.
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Dark Skies Awareness
19. Negative Impact on Human Health
• Light trespass into
bedrooms disrupts
sleep patterns.
• Glare in our eyes can
be blinding and reduce
our night vision.
• New research is being
done to discover the
impact to our biological
clocks.
IDA in Partnership with NOAO, NSF and IYA
Dark Skies Awareness
20. Negative Impact on Astronomy
• Light pollution negatively affects
one of our greatest natural
laboratories, the night skies.
• This is an important industry
that has given us
– Cell phone technology
– X-rays, MRI’s, and medical
imaging
– Satellite communications
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Dark Skies Awareness
22. Solutions
• Outdoor lights should be
“full cut-off” or “fully
shielded.” That means no
light above the 90 degree
angle.
• Fully shielded lighting can be
purchased or retrofitted
• Use timers, dimmers, and
motions sensors.
• Motion sensors in a parking
lot or on a house provide an
alert to after hours activity
that a dusk to dawn sensor
does not.
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Dark Skies Awareness
24. Types of Lamps
• There are four basic types:
– Incandescent
– Fluorescent
– High-intensity discharge
• Including: Mercury Vapor, Metal Halide, High Pressure
Sodium and Low Pressure sodium
– Light Emitting Diode (LED)
• LED technology is still relatively new
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Dark Skies Awareness
CFL
High-Pressure
Sodium
Low-Pressure Sodium
25. Incandescent
• Most common in homes
• It uses electric current to heat
a tiny coil of tungsten metal
inside a glass bulb to produce
light.
• Have short lives
• Convert most of their energy
into heat rather than light
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Dark Skies Awareness
26. Fluorescent
• Used mostly in commercial
settings
• It produces light when
electric current is conducted
through mercury an inert
gases.
• 3 to 4 times more efficient
than incandescent, and lasts
10 times longer
• Produces up to 100/lumens
per watt (approximately)
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Dark Skies Awareness
27. High-Intensity Discharge
• Used mainly for large area
applications
• Provide higher efficacy and longer
service life
• Most common types are mercury
vapor (MV), metal halide (MH),
and high-pressure sodium (HPS)
– Metal Halide – 100/lumens per watt
– HPS – up to 150/lumens per watt
– MV – being phased out
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Dark Skies Awareness
28. HID continued
Low-Pressure Sodium
• Also considered a high intensity discharge
lamp, but it has some unique
characteristics.
• Used in outdoor applications
• Most efficient form of artificial lighting
• Maintain their light output better than
other lamps
• Older technology, not many manufacturers
producing new product
• Produces up to 200/lumens per watt
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Dark Skies Awareness
29. Types of Luminaires
• Column mounted fittings:
used for streets, car parking,
cycle tracks and pedestrian
areas (pictured: Pacific Lighting model TRL)
• Wall mounted lanterns: used
most commonly for security
(pictured: Lighting by Brandford model Glarebuster)
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Dark Skies Awareness
30. Types of Luminaires
• Lighting bollards: used for
pathway and area lighting
(pictured: Architectural Area Lighting model Concrete bollard)
• Recessed fittings: used for
pathways, or where buried
in the ground for uplighting
structures, trees and other
incidents. (pictured: Deck-Lighting model deck light)
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Dark Skies Awareness
31. Following six slides show shielded and
unshielded outdoor lighting examples
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Dark Skies Awareness
33. Fully shielded lighting at an airport
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34. Unshielded lighting at an ATM
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35. A typical un-shielded mercury vapor
luminaire
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Dark Skies Awareness
36. How shielded lighting reduces glare
• The image below is a test site
for fully shielded street lights.
To the right; the same lights
shown in comparison to the
un-shielded existing lights.
IDA in Partnership with NOAO, NSF and IYA
Dark Skies Awareness
38. Designing a Lighting Audit
• We need to be familiar with some more
terms before we go on:
– Area lighting: lighting provided to illuminate
open areas uniformly
– Annual operating costs: cost per year of
electricity, maintenance including
replacement parts & labor
• This contributes to how much energy we want
to save
– Illumination: the distribution of light on a
horizontal surface, measured in footcandles
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Dark Skies Awareness
39. More things to consider
• Luminance: The photometric
quantity most closely
associated with the perception
of brightness.
• Lumens is the overall output of
the luminaire.
• Energy Use: The product of
power (watts) and time (hours).
IDA in Partnership with NOAO, NSF and IYA
Dark Skies Awareness
40. Power Density or Light Footprint
• Power density is a measure of electrical power per
unit area, measured in watts per square foot or
square meter. Many building codes prescribe
maximum power density values for various areas of
use in an effort to promote the use of energy-efficient
products.
• Unit Power Density is the energy for lighting, divided
by the outside area. Unit Power Density (W/sq.ft.) =
Total System Input Wattage (W) ÷ Total Area (Square
Feet)
IDA in Partnership with NOAO, NSF and IYA
Dark Skies Awareness
41. Pole Mounting Height
• Luminaires on poles can
provide illumination in every
direction at distances of two to
two and half times the
mounting height from the pole.
Thus, luminaires on a single
pole can serve an area of about
four times the mounting height
- squared. For example, a 50-ft
pole can cover about 40,000 sq
ft and a 150-ft pole about
369,000 sq ft.
IDA in Partnership with NOAO, NSF and IYA
Dark Skies Awareness
42. Thank You
• Good luck with your
activities, and
remember “dark
skies” does not mean
“dark ground.”
• You are now unofficial
lighting geeks.
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Dark Skies Awareness
43. Let’s get
to work!
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Dark Skies Awareness
• It’ll be fun, really!
44. Activity One -
Vocabulary
• Vocabulary
– The instructor will have a glossary of lighting terms
that the students should be familiar with before
beginning any of the activities.
– Presentations from the activities should include the
use of these terms
• Knowing the language of lighting terms will enhance the
understanding of the activity
• For lighting ordinances to be enforceable, they need to be
written with the proper language.
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Dark Skies Awareness
45. Activity Two – Energy Audit
• Audit the types of
outdoor lights on the
buildings at your
school.
• Ultimately, you will be
making
recommendations on
how to be more energy
efficient with outdoor
lighting.
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Dark Skies Awareness
46. Activity 3 - Measurements
• Choose 2 different
types of luminaires
from the audit. For
each lamp prepare at
least 2 of the following
measurements and
observations listed in
the workbook.
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Dark Skies Awareness
47. Activity Four – Master Plan
• Produce a revised lighting scheme
for your school campus or
neighborhood. Using the material
you have learned, determine:
– If all the lights in audit are now
necessary
– Review what task/purpose a lamp is
used for
• Recalculate the energy
consumption of the new plan.
– Have we saved money?
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Dark Skies Awareness
48. More Plan Considerations
• Design a visual master plan for your campus:
• What are the goals for the plan
• Show a diagram of the area
• Consider these issues (you are welcome to make your own
assumptions) and address each in your final presentation.
– How will it be used? A lot, a little? Ball Park? Walk/Cycling
path? Restrooms? Nearby parking lot? Sculpture? Fountain?
– What are the hours of use?
– What safety precautions are in place?
– Has glare been reduced or eliminated?
– What type of luminaires are you recommending and why?
– What is around your park/campus? Residential, open space,
businesses, mixed use?
IDA in Partnership with NOAO, NSF and IYA
Dark Skies Awareness
Editor's Notes
During a full moon it would be relatively bright and during a new moon, it is very dark. The picture on the top shows us what night used to be and the picture on the bottom shows us what some urban areas have become.
Yes, there has been a long history of lighting streets and homes at night. However, for much of that time it was lighting that was much softer than today’s lighting. The term candlepower comes from this history. Candlepower is a measure of luminous intensity of a light source in a specific direction measured in candelas.
This photo illustrates most of the types of lighting that we see everyday. Both the good and the bad. Which takes us to…..
All of these purposes show an excellent reason for having light at night, but perhaps we could look at the design of these outdoor lights to determine if there is a better way to light. Why is design important?
Without proper lighting design you get light pollution. Light pollution is one of those rare pollutions that actually costs less to solve than it does to continue as it is. Let’s look at what lighting engineers should consider when they design a lighting scheme.
Glare is defined as excessive brightness from a source of light in the line of sight, usually horizontal. Trespass is light that goes where it was not intended to go, wanted or needed. A master plan begins with an audit of your surroundings and what is the task that each light will take.
Safety means that light is not glaring in your face, does not cause blindness when you look at it. Good lighting is shielded and points to the ground below. No light above the 90 degree angle (or the horizontal), this is also know as full cut-off. Notice the light on the ball field above. See how it lights just the field and not the surrounding area. If you look closely you will see the lights from the window of a house at the 10 o’clock position behind the field. No light trespass is annoying this homeowner.
If we don’t consider the above elements we negatively impact our whole environment.
Sky glow is that orange haze that sits over a city and can be seen up to 200 miles away. Sky glow is exacerbated by particulates in the air: pollution, water vapor, aerosols, and cloud cover. The photo to the left is Los Angles in 1988 from the Griffith Observatory. As you can see there are no stars visible. The photo on the right shows the unsafe glare an unshielded light can produce. Do you see the man hiding on the other side of the van? The irony is, this lighting was installed to make people safe, however, now they are less safe.
Why should any of us be concerned that there is too much light at night and poor outdoor lighting design? Well there are 5 very good reasons for trying to reduce light pollution and the first one is the waste of energy is causes.
Here is an excellent example of a poorly designed lighting scheme and how it does not contribute to campus safety. Notice the glare in the trees? Well the students don’t walk there, but on the ground where they do walk there are lots of shadows.
Can you detect where the student is now? This light was meant to make the campus safer, but the lighting has only made the shadows easier to hide in. The student is now directly under the lamp, great place for a shadow isn’t it. Now we have created the shadows in which to lurk.
There is more and more research being done about the effects of light pollution on animals, but there is a lot we don’t know yet. This is what we do know. In addition no one spectrum of light is the best for all species. Yellow lights do not attract insects, however, red lights do not attract sea turtles. Good lighting design takes into consideration all aspects of the area to be lit.
The research being done on our biological clocks is going to be very interesting. Our bodies naturally produce many hormones, including melatonin when they are in total darkness. Melatonin is found in practically all species, and acts as an anti-oxidant for the body. If you have light trespass into your bedroom, this biological rhythm may become disturbed. How much light does it take and for how long? These are questions that they are studying, and when we have more information about correlations between light and health we will publish them.
Astronomy is often a “gateway” to other sciences because the laboratory is just outside. The optics perfected in telescopes has been used in satellite technology for weather and communications. Optics designs have also been modified for ophthalmic applications and diagnosis. Radio astronomers have led the way in advances to increase bandwidth for television, satellite, and radio communications. Astrophysics has been the major impetus behind super computer construction for over 50 years. Sensors and detectors have been developed and improved because of the science of Astronomy. These include x-rays used in healthcare, luggage scanners, energy research and biomedical research. Astronomical studies provide information on climate change, weather patterns, and solar observations affecting our planet. So you see, it’s to our mutual benefit to continue to provide clear skies for this research.
Promoting fully shielded lighting is the backbone of reducing wasted light and energy. These luminaires cost no more than un-shielded light fixtures. We understand that people need some lighting at night, let’s just look at it in a different way. Better lighting that does not spread the light upward where it is not needed. This photo is a perfect example for using shielded lighting to reduce glare, reduce upward light, and perhaps using a timer to dim the lights or turn them off at night. While it’s possible that someone wants to look for a car at 1:00 a.m., it is not probable.
Let’s look at the types of lamps we will see on our campus or in our neighborhood. “Lamp” is a lighting industry term for an electric light bulb, tube, or other lighting device.
LED technology is still relatively new and has not been installed on a wide basis yet. Therefore we will not be getting into details about this type of lamp in this lesson.
An incandescent lamp produces visible radiant energy by electrical heating of a filament.
A fluorescent lamp contains mercury that is ionized by an electric arc, producing ultraviolet energy which, in turn, causes a phosphor coating inside the lamp to fluoresce.
Yes, fluorescent lighting needs to be disposed of properly when it is no longer in use. Most cities have a recycling program where people can safely dispose of the burned out bulbs.
A high intensity discharge lamp (HID): produces light directly from an arc discharge under high pressure. Metal halide, high pressure sodium and mercury vapor are types of HID lamps.
A low pressure sodium lamp produces light from sodium gas contained in a bulb operating at a partial pressure. The yellow light and large size make them applicable to lighting streets and parking lots
A luminaire is a complete lighting unit consisting of a lamp or lamps, together with the parts designed to distribute the light, to position and protect the lamps, and to connect the lamps to a power supply.
A full cut off or fully shielded luminaire is one that allows no light above the 90 degree angle. These two luminaires, and the two on the next page are dark sky friendly. They allow no light above the 90 degree angle. Though you may not see this exact type of lamp, for this lesson we wanted you to be aware of the four most common types of luminaire installations.
These two ball fields show a good contrast between unshielded and shielded lighting. The field on the left is producing glare and so much of its light is wasted going into the sky. The field on the right has much less impact on the surrounding area because it is only lighting the field, not the neighborhood. Which one would you rather live next to?
This lighting not only causes blinding glare, it is so bright it exposes any user of the ATM to anyone driving by.
You’ll notice that this light sags down, also known as a sag lens, and releases light everywhere. You will also notice that it is very dim. Mercury Vapor lights never burn out they just dim down like this one. However, even though the light is no longer performing the task it was intended to, the city is still paying full price for the light to be on. Just because it dims does not mean it becomes less expensive to operate. Clearly, it is performing less effciently.
The above two pictures demonstrate a test installation in Ville St-Laurent ( a suburb of Montreal) Quebec, Canada. Photo at right is view of test installation from above compared with the existing drop-refractor HPS cobraheads. You will notice the section of the test area reduces glare and waste into the sky. The old style cobra heads (which were named because that is what the design looks like) spill light everywhere.
We now need to ask ourselves some questions about the area we would like to audit
Significance of area lighting – What are we going to light? Everything? What are the tasks going to be in this outdoor area?
Annual costs – Remember not to be penny wise and pound foolish. An incandescent light may be the easiest to acquire, but if that outdoor light is going to be on for a significant amount of time, you will be changing it often, there will be labor involved, and it is not energy efficient.
Illumination is important because we need to know the surfaces around and under our luminaire. Is it dark, is it light
Luminance is the measurement reflected off an object.
Illuminance is the measure of light hitting an object .
Energy use is very important because this will tell you how much your lighting is costing you. What is your budget?
One activity that students can participate in is determining the power density of a luminaire. The equation is listed above. You will make assumptions of the task area to be lit. If you are working in the parking lot area, you may wish to consider using the entire parking lot measurements in your equation. Just be consistent.
Can you make any assumptions about the target area? Is the light in the street? Is light from the campus shining on other property?
Inspect your campus or your neighborhood for pole mounted lights in nearby streets, parking lots, parks, or stadiums. Make observations about the light pattern of the pole mounted luminaires. Is there overlap from the street lighting to the parking lot lighting? Determine the pole height, then using the calculation of (pole height) X 4 = service area. How many lights are currently serving that area?
New luminaire design has superb optical control. So you don’t need poles closer together to control the lighting of an area.
For students it is important to know the vocabulary because many of these terms are used in multiple areas of study: math, engineering, and science. It is up to the instructor if they wish to give the vocabulary test before or after the all the activities are completed.
For adults in an action group, if they are looking to write or revise an outdoor lighting ordinance/lighting code they will need to use the proper terminology that is familiar in the industry. Otherwise, the code will be difficult to enforce.
The purpose of the audit will give the students or the action group a place to begin. We will assume for the purposes of this activity that you are in a situation that already has outdoor lighting and you wish to make it better: targeted, more energy efficient and less expensive. You can not make recommendations without a thourough knowledge of what is currently there. The activity is expained in the workbook.
In your workbook there is a complete listing of the equations necessary to complete each of these calculations. The instructor has the option of assigning more or less measurements based on time and availability of resources.
Students (individuals or teams depending on the instructors preference) will present their revised lighting scheme for the campus to the class and give explanations for the existence of each lamp. They should have a drawn up lighting scheme on grid/graph paper to show to the class.
For adults in a community they can then use this revised lighting scheme when they go to a planning & zoning meeting, or city council meeting.
An instruction option: Interview or consult with a lighting engineer or designer in your area for feedback on your design.