In the deep highlands you’d read about 22 mags/sq arcsec. In a city you’d read about 16 mags/sq arcsec. These devices give you a reading in magnitudes per square arcsecond (basically brightness per unit area in the sky). You can also get ethernet (SQM-LE) and USB (SQM-LU) ones for continuous readings. You’ll want to get the SQM-L, which is their hand-held device, and costs about $135. It’s fairly easily done, assuming you have the time and the inclination.įor a very accurate map you’ll need to buy a Sky Quality Metre, manufactured by a company called Unihedron: The light pollution map files you overlayed are the highest res we have I’m afraid, but that’s not to say that you couldn’t get a more accurate map, you’d just have to make it yourself! Shame your dark skies are being encroached upon by more and more lighting… Glad you enjoyed the Google Earth LP overlay.Īctually, I’m a highland lad myself born and raised in Inverness, so I know Ullapool well. Hints: I find it aesthetically more pleasing to disable Google Maps “Borders and Labels” in the “Layers” box Now in your “Places” bar on the LHS you’ll see your overlays, with checkable boxes to enable / disable them. This will overlay your Light Pollution maps onto the globe accurately (but you might want to tweak and fine tune to get the perfect fit – let me know if you get an even better fit than I did and I’ll adjust the co-ordinates above to match).Ĩ. Click on the “Location” tab and enter these co-ordinates: Move the transparency slider to between 25% and 50%ħ. In the “Image Overlay” box enter a suitable title, such as “Naked Eye Star Visibility”, then browse to find the. Open Google Earth, click on Add > Image Overlayĥ. Unzip the file (both of the above links are zipped files of large. Naked Eye Star Visibility (Western Europe): ģ. Download the appropriate light polution map:Īrtificial Sky Brightness (Western Europe): or Download Google Earth and install it on your computerĢ.

Dark sky overlay