Dark Site Finder: A Light Pollution Map for Finding Real Darkness

Dark Site Finder is a map of the world colored by how much artificial light is being thrown into the sky. Cities glow white and red. Suburbs are orange and yellow. Out past that it goes green, then blue, then gray, and the gray is where you can see the Milky Way with your own eyes, no equipment, standing still.

For anyone who has ever bought a telescope and been disappointed, this map is the actual fix.

What is Dark Site Finder?

There is a widely held assumption among new stargazers that better optics are the answer. They are not. Light pollution is the answer. A modest pair of binoculars in a genuinely dark place beats an expensive telescope in a suburb, and it is not close, because no lens can subtract the orange glow that a town is pumping into the atmosphere all night.

Dark Site Finder makes that visible. It takes sky brightness data derived from satellite measurements of artificial light and lays it over a standard map interface as a color-coded overlay. You pan to where you live, look at the color under your house, and then look for the nearest patch of a different color.

The color scale is the whole interface, and it maps roughly onto the Bortle scale that astronomers use to describe sky quality. White through red is the worst: bright suburban and urban skies where a handful of stars and the planets are all you get. Orange and yellow are transitional. Green and blue are rural skies where the Milky Way becomes apparent. Gray and black are the good stuff, sites where the sky has visible structure and your own shadow can be cast by starlight.

The site also maintains lists of specific dark sites, places people have actually driven to and observed from, with notes. That is a useful supplement, because a dark pixel on a map might turn out to be a private field, a mountainside with no road, or a spot with trees blocking the whole southern horizon.

It has been running for years as an enthusiast project. The interface is functional rather than beautiful, which is the correct priority for a tool people open at 9pm while deciding whether to get in the car.

What can you do with Dark Site Finder?

• Check the sky over your own house. Usually the moment people realize why they have never seen the Milky Way. Start here for the calibration.
• Find the nearest darker zone. Pan outward and look for the first meaningful color change. For most people in developed regions it is a surprisingly short drive.
• Plan an observing trip. Combine the map with a road map and pick a target zone, then find a legal, accessible spot inside it.
• Compare regions before traveling. Useful for choosing where to go if the trip is partly about the sky, and for setting expectations if it is not.
• Browse the dark site lists. Specific locations recorded by observers, which saves you discovering a promising gray patch is fenced off.
• Sanity-check a campsite. Before booking, look at what color it sits in. It costs nothing and it changes which night you plan the stargazing for.

Tips to get the most out of it

One color step is worth more than any gear purchase. Moving from orange to green does more for what you can see than anything you can buy. Treat the map as the first upgrade, not the last.

Check the moon phase separately. The map only shows artificial light. A full moon in a gray zone is brighter than new moon in a green one, so aim for the nights around new moon and let the map handle the rest.

Look at the terrain, not just the color. A dark pixel in a valley with high ground to the south is worse than a slightly brighter pixel on an open ridge. Switch to a satellite or terrain view before committing to a spot.

Pick a legal, accessible location. Dark areas are dark partly because nobody lives there, which often means the land is private or the road is unpaved. Public land, designated dark sky parks and established pull-offs save a lot of awkwardness at midnight.

Give your eyes forty minutes. Full dark adaptation takes far longer than people expect, and one glance at a phone screen resets it. Use a red light, and do not check the map again once you have arrived.

Look at the direction of the glow, not just the amount. If the nearest city is to the north and you mainly want the southern sky, a site closer to that city than you would like can still work fine.

If you like Dark Site Finder, also try…

• 100,000 Stars: what is actually out there, plotted in 3D, for the nights you cannot get outside.
• WorldWide Telescope: real survey imagery of everything you are trying to squint at.
• Windy: cloud cover forecasting, which is the other thing that ruins an observing trip.
• earth :: nullschool: the atmosphere you are looking through, rendered as a spinning globe.

More reasons to drive somewhere remote in Maps & Exploration.