mirna kramar, petra korlević, Željko andreić

Analysis of light pollution influence on sky quality in Istria

a.k.a.: The “glow in the dark” group

Analysis of light pollution influence on sky quality in Istria

a.k.a.: The “glow in the dark” group

Mirna Kramar, Petra Korlević, Željko Andreić

Light pollutionLight pollution

• Serious problem in astronomy, ecology, psychology...

• Specific categories– light trespass– over-illumination– glare– clutter

Sky Quality MeterSky Quality Meter

• sky brightness– mag/arcsec2

• World:– The best: 23.14

(Cherry Springs State Park, USA)

– The worst: 12 (Langhus, Norway)

Sky brightness [mag/arcsec2]Sky brightness [mag/arcsec2]

• Tičan: 21,0• Višnjan: 20,7• Pula: 18,9• Rt Kamenjak: 21,0• Premantura: 19,8• Vodnjan: 19,3• Savičenta: 21,0• Kanfanar:20,8

How fast does the sky dim?How fast does the sky dim?

7

9

11

13

15

17

19

21

23

20:09 20:38 21:07 21:36 22:04 22:33 23:02

time

sky

bri

gh

tnes

s [m

ag/a

rcse

c^2]

20:50 21:29 22:13

12,00

14,00

16,00

18,00

20,00

22,00

20:47 20:57 21:07 21:17 21:27 21:37 21:47 21:57 22:07 22:17

Time

Sky

bri

gh

tnes

s [m

ag/a

rcse

c^2]

Tičan

Cloud influence on sky brightnessCloud influence on sky brightness

20,15

20,2

20,25

20,3

20,35

20,4

20,45

22:33 22:40 22:48 22:55 23:02 23:09 23:16 23:24 23:31

Time

Sky

bri

gh

tnes

s [m

ag/a

rcse

c^2]

Višnjan

Inhomogeneity of sky brightnessInhomogeneity of sky brightness

20,7

20,8

20,9

21

21,1

21,2

A B C D E F G

location

sk

y b

rig

htn

es

s [

m/a

rcs

ec

^2

]

1st measurement 2nd measurement 3rd measurement average

All-sky imagingAll-sky imaging

• Inox all-sky mirror (spherical)

• tripod• Canon EOS 300D /

EOS 20D• Lens: 37mm f/4

[Russian]• nice, clear weather...

Sky in IstriaSky in Istria

• “Istria by night” side-project

• EOS 20D: 5min exp, ISO800, [Raw+M]

Tičan&VišnjanTičan&VišnjanT

ičan

Viš

nja

n

Southern Istrian locationsSouthern Istrian locations

Vodnjan PulaCape

Kamenjak

Middle Istrian locationsMiddle Istrian locations

Kanfanar Savičenta

Main pollutants of Istrian skiesMain pollutants of Istrian skies

• North: Kopar, Trieste, Umag, Novigrad, Poreč...

• Middle: Kanfanar crossroad, Žminj, tobacco factory...

• South: Vodnjan, Pula, Premantura, Medulin...

Mapping street lamps in VišnjanMapping street lamps in Višnjan

• 197 lamps – 1km radius

• 168 in 2001

...with special thanks to Dino :)...

Percentage of lamps by typePercentage of lamps by type

41%

32%

15%

5%7%

Hg Na tung banner halo

52%

21%

13%

4%10%

2001

2006

ConclusionsConclusions

• Sky brightness: best/worst• Tičan Observatory vs. Višnjan Observatory• Situation in Istria• Višnjan: 85 “new” lamps 14 cutoff

TO DO• Correct the scale• East coast?• Istria by night Croatia by night

“If we could see the stars from just one place on Earth, people would never stop going on a pilgrimage to that place for seeing them” ~L. A. Seneca