Light pollution map

Review by eFreeware

Anyone who has driven an hour out of town expecting a dark sky, only to find a glowing horizon from some industrial estate, knows the problem this app addresses. Light pollution is uneven and invisible on an ordinary road map, so planning a night out for stargazing or photography often comes down to guesswork. Light Pollution Map, from developer Deneb, Jurij Stare, s.p., sets out to replace that guesswork with satellite measurements of how bright the night actually is.

It sits in the Maps & Navigation category and costs $5.49 as a one-time purchase. The app has been on Google Play for several years and was updated recently.

That combination — a small, paid, quietly maintained utility — usually signals a tool built for a specific job rather than a broad audience. Here the job is finding and comparing dark locations, and the sections below look at how the app goes about it.

Satellite data behind the map

The core of the app is an interactive world map layered with night-time radiance readings from VIIRS, specifically the Black Marble 2.0 dataset. This is satellite night-time radiance data, the same source research institutions and environmental agencies use to monitor how bright the night sky has become. The dataset behind the map is a credible one to build on.

What you see is sky brightness rather than a simple city-lights picture. The map is global and detailed, and you can switch between several light pollution datasets rather than being locked to a single view. There is also a color-blind option for the overlays, which is a thoughtful touch for an app whose whole value rests on reading a color gradient correctly.

The map reflects measured radiance rather than a rough estimate drawn from population centers. That matters most at the margins — the difference between a site twenty minutes from a small town and one an hour further out is exactly the kind of thing a radiance map can show and a general-purpose map cannot.

Reading brightness in Bortle and MPSAS

Raw radiance numbers mean little to most observers, so the app translates them into two scales that amateur astronomers already use. MPSAS, or magnitude per square arc second, gives a numeric brightness figure, while the Bortle scale places a site in one of the familiar classes from inner-city to pristine dark sky. Having both means you can compare a candidate location against a site you already know, which is a much easier judgment than interpreting a heat map alone.

A brightness simulation tool goes a step further, letting you see what the sky at a given spot would look like at a chosen level of light pollution. For anyone deciding whether a location is worth the drive, that is more useful than a number on its own, because it turns the reading into something closer to an expectation.

The map also carries additional layers. Since moonlight is often the limiting factor on an otherwise dark night, having that alongside the pollution data helps with picking a date rather than just a place.

Planning tools for a night out

Beyond reading the map, the app includes a set of tools for working with it. You can pull point or area information from a spot, run a search for the closest dark site, and look at VIIRS country statistics if you want a broader picture of how a region compares. The closest-dark-site search is the feature I would expect to get the most use, since it answers the practical question directly rather than leaving you to scan the map by eye.

There is another layer as well, which addresses the other common reason a carefully chosen dark site disappoints. Another layer is included too, aimed at a different kind of night-sky outing but sharing the same need to judge conditions in advance.

The app also includes additional data layers alongside the satellite data. That is a neat way to keep personal readings in the same view as the modeled brightness, and it gives the map a second, ground-level source of information to compare against.

History, layers and saved places

Light pollution is not static, and the app lets you see how brightness at a location has changed over time. For anyone weighing a long-term commitment to a site — a backyard setup, a regular camping spot — that comparison is more informative than a single snapshot, and it is the kind of feature that separates a data tool from a pretty overlay.

The recent update added ways to organize your own material. Feature filters can now be saved in settings, and the name field supports wildcard searching. Saved locations can be organized and displayed on the map. For someone who returns to the same handful of sites, or who keeps a list of places worth trying, that turns scattered notes into something the app can show you directly.

The update also changed the calendar widget so that adjusting dates no longer brings up the virtual keyboard — a small fix, but the sort of thing that matters when you are entering a time in the dark.

What it needs and what it costs

The app is a paid download at $5.49. You buy it once and keep it. For a tool you might use a few times a year, that is a straightforward arrangement, and it avoids the usual question of what a free tier leaves out.

The World Atlas 2015 dataset can be cached, so that layer can be kept on the device, while the rest of the app is built around map data and satellite layers.

The other consideration is the nature of the tool itself. It reports on sky brightness and conditions; it does not tell you where you are allowed to be, whether a site has parking, or how to get there. It is one input into planning a night out, and a specialized one. The app stays close to its subject rather than branching into general trip planning.

Who the map is built for

The people most likely to get value here are those who already plan around the night sky: astrophotographers scouting a location before hauling equipment out, stargazers looking for a darker alternative to their usual spot, campers who would rather wake up somewhere with a decent view overhead, and anyone chasing the Milky Way or a meteor shower. People interested in light pollution as a subject rather than just as an obstacle will find plenty here.

The casual end of the audience is served too. If you are simply curious how dark the sky is where you live, or whether a nearby park is meaningfully better than your backyard, the map answers that without requiring any background in the scales it uses.

Where I would temper expectations is in treating it as a complete observing companion. It is a specialized reference for one variable, and it expects you to bring the rest — a location you can actually access, a forecast, and a night when the clouds cooperate. Judged on that narrower purpose, the combination of satellite data, standard brightness scales and planning tools covers the ground well.

A worthwhile purchase for sky watchers

Light Pollution Map does one job with unusual thoroughness: it shows you how bright the night sky is, anywhere in the world, and gives you the tools to act on that. The app's features add up to a genuinely useful planning instrument rather than a single-purpose overlay. Saved filters and locations make it easier to keep your own reference points in view.

The $5.49 price makes the cost easy to justify for anyone who goes looking for dark skies more than once or twice a year. Buyers have generally found it worth the money.

If you are an astrophotographer, a regular stargazer, a camper who cares about the view after dark, or someone who simply wants to know how their local sky compares, this is a sensible purchase. If you need turn-by-turn directions to a campsite or a full weather forecast, this app is not trying to be that, and it is honest about its focus.

What's new in version 1.1.42

- Feature filters can be now be saved (settings). Name field also supports wildcard searching for example '*town OR john*' will display 'Smalltown' and 'Johnstown'. - 'My locations' can now be saved (and edited) and restored from a file. - 'My locations' now also available as a feature overlay, so you can view them on the map. - Changing dates in the calendar widget doesn't open virtual keyboard anymore (except when you tap on hour/minute fields). - Other minor changes and bug fixes.