Monday, December 2, 2019

Second action of the Nachtlicht-BüHNE outdoor lighting project

Nachtlicht-BüHNE is a co-Designed Citizen Science project related to light at night, funded via the CitizenScience@Helmholtz initiative of the Helmholtz Association in Germany.
Within the project, citizen scientists will be developing two apps. The first, coordinated by the German space agency (DLR), is about improving the system for reporting sightings of fireballs in Germany. The second, coordinated by the German Research Centre for Geosciences (GFZ), is about creating large-scale inventories of all outdoor lighting. This means we are interested not just in street lighting, but also private lights, lighting for advertisement, industrial lighting and so on. For more detailed background, see the previous blog post from September 5th

This work by Markus Schönrock is licensed under
a Creative Commons Attribution 4.0 International License.
To get to the point: there are no exhaustive databases categorizing all outdoor light sources (in contrast to the situation for streetlights, for which there are some public databases). In order to understand the radiance observed by satellites, we therefore need information about what types of light sources are producing the light. We would also like to understand how the types of light source change depending on whether the satellite is viewing a small town, suburban areas, or city centers. This project aims to develop an app to allow citizen scientists to record and count outdoor luminaires, creating one of the first datasets of this kind…you can be part of it!
Before we can develop the app, we need to figure out how to make it work well. We are planning on producing two versions app the app: a Basic version with the minimum requirements, and a Pro version that allows more detailed information to be recorded. We are starting with the Pro version, and this is where we need your help right now:
We have a special form for you to record the data. You should send us your record by January 5th, 2020 to Also, please feel free to send us your feedback about what worked, what didn’t, and any problems and further ideas you have about our approach.
Here are the detailed instructions:
  • Find a friend
  • Print out our paper form
  • Have a look at the form from start to end, so you that you are familiar with the different categories and attributes of the luminaires. (For example, we also count illuminated windows, which might at first sound crazy, but actually does not take that long and turns out to be really important.)
  • Choose a starting and ending location (typically a single street from one intersection to another).  
  • Get a pencil or pen, and then take the form and meet your friend at the starting location.
  • Write down the time you started.
  • Start walking slowly down the street, recording ALL the light sources you can see. We find it works best for one person to spot the lights, and the other to record which type they are.
  • When you reach your stopping point (eg. the next intersection), write down the time you finished
  • Optional: do another street! (But with a new form, please!)
  • When you get home, type your observations into this Excel form, and save it.
    • Record the coordinates of your segment on the form in decimal degrees (WGS84, for example 52.5163N, 13.3777E). You can find the coordinates using Google maps or Openstreetmap.
  • Send us your data and your thoughts about this paper version to by January 5th 2020.

Finally, some additional hints regarding the lamp categories:
  • Most of the time we count the number of luminaires we see – if a street lamp more luminaires (e.g. a  candle tree with two arms) we count each of them individually (so two)
  • Sometimes counting is not enough in categories where the luminaires vary greatly in size (e.g. illuminated signs outside of shops). In this case, we have three size categories, and you count the times the luminaire fits into them (e.g. a sign roughly as big as two hands counts as two hand-sized signs)
  • Full cutoff luminaires: this is a lighting fixture that projects all of its light in a downward direction – it can sometimes be tricky to tell if a street light is very high up. Here some hints to help you with determining if a light is full cutoff:
    • The light source is fully inside of the fixture, it does not hang below it.
    • The glass below the lamp is entirely flat, not curved
    • The fixture is directed straight downwards (not tilted at an angle) 
    • No light should shine above the height of the lamp (if a nearby house or tree is lit at a level higher than the lamp, it’s not full cutoff) 
  • Normal versus bright: humans cannot reliably estimate small differences in brightness, but we can identify particularly glaring light sources. So we want to record separately light sources that seem particularly bright to you compared to the rest in your street segment (e.g. the lighting at a zebra crossing, an extraordinarily bright shop window or sign etc.) 
Paper form
Excel form
Do not make observations alone! With two people, you will do a better job of keeping track of your surroundings. But it’s also much easier and a lot more fun to do it with a friend or family member! 

This work by Markus Schönrock is licensed under
a Creative Commons Attribution 4.0 International License.

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