Željko Andreić: Introduction to light pollution, P3 1

Introduction to Light Pollution

Lecture 3

prof. Željko Andreić

Faculty of Mining, Geology and Petroleum EngineeringUniversity of Zagreb

zandreic@rgn.hr

http://rgn.hr/~zandreic/

Željko Andreić: Introduction to light pollution, P3 2

Contents

1. sources of artificial light2. basic lamp characteristics3. "good" and "bad" lighting fixtures

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Street light

lighting fixture

pole

support

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Lighting fixture

case

support

protective glass

optics

control electronics

light bulb

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Tungsten light bulb

vacuum

filament

glass bulb

holder withelectrical contacts

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Fluorescent tube

rarefied noble gas

glass tube with phosporous coating inside

electrical contact

electrode

mercury

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High pressure vapour lamp

aluminaarc tube

holder withelectrical contacts

glass bulb

noble gas

alumina tube

electrode

volatile metal (Na,etc.)

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LED

LED crystal

transparent casing/lens

electrical contacts

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Polarn diagram of luminous intensity

90o-90o

180o

0o

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Usefull and useless light

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A very bad light fixture (luminaire)

Difuzna kugla sa žaruljom u sredini, 35% svjetla ide prema dolje a 40% prema gore!

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Prozirna kugla sa optikom i žaruljom u sredini, 58% svjetla ide prema dolje, a 17% prema gore

A bad light fixture

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Zatvorena lampa sa optikom, 68% svjetla ide prema dolje, ništa prema gore!

A good light fixture

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Very bad, bad, good...

opaque globe, 5m

transparent globe and optics, 5m

closed

luminiare, 8m

300 m road: 20x150 W = 3000 W

300 m road: 15x150 W = 2250 W

300 m road: 12x150 W = 1800 W

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How to reduce light pollution:

Bad Good

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Bad Good

How to reduce light pollution:

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Bad Good

How to reduce light pollution:

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Bad Good

How to reduce light pollution: