Colored markers show where astronomy-specific weather forecasts, or "clear sky charts", are available.
The colors of the markers indicate
amount of light pollution there (colors defined here). You can:
hover over a colored marker to show the chart's name
Click on a maker to display a the small version of the chart, and link to the full version
Click and drag on the map to pan.
Double click on the map to pan and zoom.
Even though this map can be zoomed out to show the all of North America, this page only shows charts in
Massachusetts. The full list is here.Clear Sky Chart Home | Danko's Homepage -- Python Powered