The Fourth Light Pollution Theory, Modelling, and Measurements Conference, Zselic (Hungary, June 25-28, 2019), and its workshop

Between June 27 and July 1, 2019, I had the opportunity of attending with the BuioMetria Partecipativa project a part of the fourth “Light Pollution Theory, Modelling, and Measurements” and a workshop connected to the conference. Here you will find a brief summary of the event and the experimental activities related to it, and some highlights (or should I say “high lights”) from the trip from Toscana to Hungary.

Also, please note your next opportunities to interact with BuioMetria Partecipativa and interdisciplinary night promotion and protection: July 16 in Milano, for an outreach event with Wim Schmidt, one of the main Dutch experts on this topic, and from July 25 to 29 in Southern Tuscany, with a visit by prof. Zoltán Kolláth, the mastermind of all the Hungarian events portrayed below, as well as a great progressive rock fan.

A satellite image of Italy at night (from the VIIRS sensor for June 29, 2019)

Now, back to the LPTMM conference (from June 25 to June 28). This is a bi-annual meeting attracting the main world experts in the field. After the main event, an experimental workshop was scheduled, inviting researchers to conduct night sky quality measurements with different techniques, spanning from the dear, old, Sky Quality Meter (which we called buiometro in Italy), to a plethora of imaging systems complemented by rather sophisticated processing workflows.

Such developments in sensing techniques also reflect the maturity on the light pollution monitoring topic. In the Nineties the focus of the experts was in the mitigation of light pollution effects in relation to night sky observation, as a priority mainly deriving from astronomers in order to reduce the amount of light improperly directed upwards. In the following years, with a greater awareness of the negative effects of the blue component of night lights, and its impact on ecology and landscape, measurement systems have evolved in order to detect such information. Essentially state-of-the-art technology requires the acquisition of “all sky” images, allowing to assess the source direction of lights, as well as spectral data. Combining such information, and integrating it with remote sensing data, as well as drone-derived information, extremely detailed scenarios can be assessed, thus supporting policies and management strategies for lighting systems.

The conference was in the Zselic dark sky park, in the South-West of Hungary. This is one of the three dark-sky areas certified by the International Dark Sky Association, and catered like babies by Zoltán Kolláth: in addition to managing the certification process, in the years the professor has fostered a series of lighting renovation projects in the villages around the “night sky reserves”, developed a structured research, and promotion activities on night sky-related issues.

The participants to the 2019 LPTMM conference in Zselic, with folks from (going East from Hungary): China, Canada, USA, Ireland, Portugal, Spain, Italy, Germany, Slovenia, Poland.

A photo report of the “buiometric” mission and the LPTMM workshop (June 28/July 1 2019)

Lights on in full daytime in Pisa
Lamps with different colour temperatures in Udine (different colour temperature in lamps is not a priori a problem, but it can be well noted here and makes us consider the colour temperature of light as an issue more people should account for)
Lights on in full daytime in Budapest Kelenföld. Possibly these are managed with the same system as Pisa (and other sites we are documenting)
Villages in rural Hungary, approaching the Zselic area.
Hungarian is intriguing for me. Some words are similar to the dialect from Sassari, in Sardinia, and it is impossible to memorize more than one word per day.
The opening of the workshop. “Captain” Kollath, explains to the team the strategy they will be adopting in the three nights to follow.
The main observation point for the workshop. To the South, the Zselic forest.
This is an example of the night sky from the same point, with a night sky brightness around 21.7 magnitudine per arc square second (apart from the Milky Way, please note the number of stars).
A part of the tripods used for the instrumentation. On the background some of the nightscapes visible from Zselic
Hand-made light poles at the entrance of the visitor centre hosting the workshop
Zoltan setting up his spectrometer
The installation of another sensor (an SQM with various colour filters)
One of the spectral readings during the night (with astronomincal twilight not yet over, so that solar radiation is still visible on the left part of the spectrum)
Zoltán Kolláth and Andreas Haenel comparing all-sky images acquired with different sensors (visible vs. infrared). This helps to discriminate LED light sources from lighting of other type.
Kudos to Kai Pong Tong. In 2015 he was part of the team for the night sky quality measurement campaign in Torniella, Tuscany, and eventually he used a picture of the village’s bell tower as a cover for this PhD dissertation.

We thank the conference organizers for their hospitality, and grant EFOP- 3.6.2-16- 2017-00014, “Development of international research environment for light pollution studies” for support to this mission. For more information: