Now that the dark evenings are returning and people will have more opportunity to get out under the stars I wanted to remind you of a couple of mobile phone apps that can be used to measure how dark your skies are.
Both of these apps are integrated into the “Globe at Night” project and the readings you submit will appears on http://www.globeatnight.org/map/
Firstly, for iphone only, we have The Dark Sky Meter App, https://itunes.apple.com/us/app/dsm-iyl-2015/id626796278?mt=8 . This works by using the phones camera to estimate sky brightness and works like a Sky Quality Meter. I don’t have an iphone so I can’t comment on how good a job it does!
Secondly, for both android and iphone is the “Loss of Night” app. http://lossofthenight.blogspot.de/2015/01/brief-introduction-to-loss-of-night-app.html This works by prompting you with a star chart and asking if you can see fainter and fainter stars to determine the naked eye limiting magnitude. The app also supports entering data from an SQM if you have one. The app has a ‘nighttime’ option which dims the screen and uses only red colours to help preserve your dark vision.
And for those that don’t use smartphones, ‘Globe at Night’ produces starcharts to allow you to estimate the limiting magnitude and submit your readings via their website http://www.globeatnight.org/5-steps.php