analysis of light pollution influence on sky quality in istria a.k.a.: the “glow in the dark”...
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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