Ever wish you could pull up a map and easily roam around looking for a
dark sky sites? If so, here's a very cool and easy way to do it with
Google Earth and images provided by the Light Pollution Science and
Technology Institute of Italy.
You need the Google Earth program loaded onto your PC. Get it here
if you don't already have it (the free version is what you want):
click here.
Download the light pollution map for North America:
click here.
After the file is downloaded, unzip the .tif file and save it to a
known location on your disc drive.
Start Google Earth and choose Add|Image Overlay from the menu.
Give the new overlay a meaningful name like "Night Sky" or
anything else to your choosing.
For the "Image URL or Filename" prompt, click on the Browse
button and find and click on the .tif image you just
unzipped. Since I saved my .tif in C:\home, I used
"C:\home\global_northern_Vb.tif".
Click on the "Advanced" check box and fill in the following
boundary coordinates:
N: 55.076405
S: 9.210841
E: -59.429179
W: -126.158321
You'll want to adjust the opacity of the overlay so you can
still see the underlying roads and terrain beneath the
light pollution overlay image. An opacity between 25% and
50% seems to work well for me.
When you are done, it should look something like this:
Click OK to save these settings.
The image layer "Night Sky" (or the name you used) will now
be in your "Places" box. Here is a cropped screen print of
my "Places":
Click the check box next to "Night Sky" (or the name you used)
to activate the image layer. Example:
Here is a view of Florida with the "Night Sky" image layer on:
