The Loss of the Night app project passed another milestone today, with the 15,000th observation being submitted early this morning. The observation was made by an anonymous user in New Jersey, USA under partly cloudy skies. The naked eye limiting magnitude was about 4, with 5 of 7 stars observed.
As I noted when we passed 10,000 observations, most submitted observations are not made under ideal conditions. Sometimes people test or demonstrate the app indoors, sometimes the moon is up, and very often (as in the case of observation #15,000) the sky isn't clear. But through the dedication of our participants, we are continuously building up a record of how skyglow is changing worldwide.
Now the race is on to observation #20,000. To celebrate that milestone, I will again send a holographic postcard to the registered user who makes a complete
observation (7 or more stars, no moon, no twilight, no clouds) with the
observation number closest to 20,000.