Brilliant zodiacal light on light polluted skies over darkest Austrian Alps

                                report prepared by Andrej Mohar, Dark-Sky Slovenia

Last night (Oct. 26-27, 2009) Andrej Lap and me were able to watch and image fantastic zodiacal light at Emberger Alm which was extremely bright for more than 2 hours (from 3 to 5 AM). It seems that 1900m elevation helps, because atmosphere thickness at such elevation is lower than at sea level. The sky was very transparent, no wind, temperature +1oC. We really enjoyed almost fantastic sky. If I compare 21.4 magnitude sky at Zaplana (600m) and 21.4 magnitude sky at Emberger Alm – Emberger Alm was far more superior, most probably because of thinner atmosphere and higher transparency.

Austria (most probably) and Slovenia (for sure) were yesterday completely covered by thick clouds. This means as there was no light pollution coming from areas with diameter of more than 100 km. Despite this you can see that skies both at Nockalm (2000m) and at Emberger Alm (1900m) were very much light polluted. On image you can see light coming from Italy (mostly), from Switzerland and from Germany.

Photo 1

Photo 1 (up): allsky image obtained at Emberger Alm (1900 m) on Oct. 26, 2009 (4h28UT) with Canon 5D DSLR and 8mm, f/3.5 Sigma fisheye lens. Exposure time was 3 minutes at ISO 1000. The main sources of artificial light that affect the sky brightness over the Nockberge are coming from Slovenia (south), NE Italy (SW) and Switzerland (west). Photo 2 (down): Sky brightness map of left image obtained with software prepared by DS Slovenia. Copyright © 2009 by A. Mohar, Dark Sky Slovenia

Photo 2

This is a clear evidence and confirmation THAT WE HAVE TO REDUCE LIGHT POLLUTION IN ALL CITIES! On images (please also remember my images from Croatia and Slovenia) you can see that northern Italy is a huge source of light pollution which degrades skies in France, Switzerland, Austria, Slovenia and Croatia. All light pollution on images of Nockalm and Emberger Alm came from distances greater that 50km (valleys below mountain were covered by thick clouds, most villages in Austria switched-off light after 11 PM – this is great!). But it is not enought! Lastovo is still superior, because there is so much dark sea (if there are no fishing boats) east, south and west of island. Grossglockner is not far away from Emberger Alm, so we could expect similar results, maybe 0.1 magnitude darker sky, but still not natural dark sky.

The attached images lead us to conclusions that even in Atacama, Chille, a good light pollution protection with diameter of 100 km is not sufficient. Atacama’s advantage is for sure very low humidity and relatively high elevation (if we talk about LP only).

Our work from yesterday is a new confirmation that we need to change complete lighting on our planet. To push 4 protection zones is a strange, not scientific and a mislead. It does not help! Maybe it helps lighting industry, but for sure is not a solution for our environment. I hope that professional astronomers will start to push more strongly a global reduction of light pollution. To preserve 4 or 40 astronomical sites is simply not enough. Astronomy is not just 40 sites, it means more than 1 million amateur astronomers and more that 1 billion starry sky lovers.

We need 0% emissions above horizon on planet Earth (including decorative pollution), we have to switch off lights in all villages after 11PM, we have to ban blue lights and we have to switch-off all highways. Austria and Germany could be a raw model regarding highways. Austria is for sure a leader for no lights in villages after 11PM.

Attached images are confirmation that there is no single point of natural dark sky in Alps. Highest and most remote parts in Alps are already light polluted.

P.S.: Attached photos were done after 2 x 11 hours work and we drove 470 km (LP contributes to CO2? emissions, for sure in many ways…) We currently improve our LP reduction software. This is why attached images are just first quick approximation done by our old LP software and images are for your personal use only. Please ask for final images in case that you would like to publish them.