Originally posted on Dark Sky Diary by Steve Owens @darkskyman
Over two weeks between 21 February and 06 March 2011 you can take part in the international project GLOBE at Night, an annual 2-week campaign. During GLOBE at Night, you can record the brightness of your night sky by matching its appearance against the constellation Orion with star maps of progressively fainter stars. Your measurements are submitted on-line and a few weeks later, organizers will release a map of light-pollution levels worldwide. Over the last five GLOBE at Night campaigns, volunteers from over 100 countries have contributed 35,000 measurements.
So what exactly do you need to do? It’s simple, just visit the GLOBE at Night website and follow their instructions. You’ll need to:
1. print out the Orion maps from the activity pack
2. go outside and find Orion. Make sure you wait till it’s properly dark, which is after about 2015 your time. Hint, Orion will be towards the south, and looks like this:
3. compare what you see with the seven Orion maps, and note down which one it looks like the most. This will tell you the magnitude (brightness) of the dimmest stars you can see
4. report your observation using the GLOBE at Night web app or through their website including the date and time you made the observation, and your latitude and longitude (don’t worry, there’s an interactive map that’ll help you find these).