Light Pollution in the Pfalz – an International Problem!

The Nature Park Pfälzer Wald and the French/German UNESCO biosphere reserve Pfälzer Wald / du Nord are a relatively dark region in the Southwest of , though densely populated and therefore bright areas are close by.

A group of 6 students (Stefan Altschuck, Fabian Friedelt, Alexander Gust, Katja Hoffmeister, Nico Lörsch and Marcel Schäfer) of landscape planning at the Technical University Kaiserslautern (Prof. Dr. K. Tobias) studied during the summer semester 2015 possible dark places in the UNESCO biosphere reserve and took there measurements of the sky brightness. Together with more students an excursion into the Pfälzer Wald was planned in the night July 16/17.

Meeting and departure in Kaiserslautern

Burgruine Lindelbrunn

First station was the castle Lindelbrunn (alt. 438 m) near Vorderweidenthal. Twilight was not yet ended, but the light domes were clearly visible.

Allsky picture taken at Burgruine Lindelbrunn, exp. time 30s, 1:2.8, 800 ISO

This allsky picture has been transformed to horizontal coordinates with the interpretation of the light domes given under the picture. And a comparison with VIIRS data from December 2014.

Very prominent in the South is the light dome of Strasbourg (470 000 inh.) at a distance of about 65 km. The more reddened color indicates a farther away light dome. The light domes of Karlsruhe and the Rhein-Neckar-Region (, Mannheim and Heidelberg) with much more inhabitants and nearer (see list) are less prominent, indicating that Strasbourg is much brighter illuminated.

Distance Inhabitants Frankfurt/Mainz 90 – 100 km 1,5 Mio. Ludwigshafen/Mannheim/Heidelberg 56 km 1,2 Mio. Karlsruhe 40 km 700 000 Strasbourg 65 km 470 000 Pirmasens 22 km 40 000 Ramstein 40 km Kaiserslautern 35 km 100 000

Fisheye pictures taken towards the South and towards the North

The horizon towards the North is still bright due to the twilight. But a bright light source of whiter color is visible at the horizon. Later during the night the sky was covered but from a viewpoint about 13 km further to the North (Luitpoldsturm, alt. 607 m) the bright light source could be separated in individual beams.

Light source in the North (Ramstein) from Burgruine Lindelbrunn and Luitpoldturm

Luitpoldturm/Hermersbergerhof

The night before (July 15/16) the sky was clear near the P south of Hermersbergerhof but due to the limited horizon view, light domes are less conspicuous. However the domes of Strasbourg in the South, of the Rhein-Neckar area in the East and Ramstein in the North can be recognized.

Allsky picture taken at the parking south of Hermersbergerhof (m= 21.2 mag/arcsec²)

Generally the region of the Pfälzerwald in the foreground appears dark, while the background sky is illuminated.

Many of the villages have changed the lighting to full cut-off 4000 K LED lighting. The brightness levels are however very different!

LED street lighting in Bundenthal (left) is about 3-4 times brighter than in Vorderweidenthal

The bright light in the North is the lighting of Ramstein Airbase which is also the brightest point on the DMSP and VIIRS pictures. It is due to indirect lighting from flood lighting towards a reflector with the light beam larger than the reflector. This is an unnecessary waste of energy and could be easily avoided, by applying one of these simple measures:

• Switch-off of the outer flood lamps • Shielding the outer lamps that the light is only directed towards the reflector • Decreasing the distance between luminaires and the reflector that less or no light will pass by the reflector • Increasing the area of the reflector

Is the illumination of the church in Fischbach, the biosphere house and the house of sustainable development at Johanniskreuz during all the night sustainable?

Nike-Stellung/Braunsberg

The potential observing platform Nike-Stellung is mainly dominated by the lights from Pirmasens. A. Hänel, 7/2015