Light Pollution Map

A few weeks ago, The New World Atlas of Artificial Night Sky Brightness was published in Science Advances. The article is a report on artificial sky radiance, a current update to previous data. The supplement to the article is a light pollution map. Since I didn’t like the quality of the CIRES web visualization of the data, I decided to create a vectorized version. As the GeoTIFF source map isn’t publically available, I used the provided KMZ preview as a starting point. After extracting and assembling the JPEG tiles, I used a bilateral filter and other processing to remove the compression artifacts and convert the image into a usable state. I then used GDAL to apply coordinate information to the image and used makesurface and tippecanoe to create vector tiles of the map. Finally, I visualized the data using the Mapbox Dark style.

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Updating Nugacious

A bit over a year and a half ago, I wrote Nugacious, which provides random quantity comparisons. However, I’ve found a lot of the comparisons to be a bit too random, being things I had never heard of. I finally got around to mitigating this issue, by weighting potential comparisons by popularity. The quantity data Nugacious uses is from DBpedia, which is extracted from Wikipedia. Since each data point is linked to a Wikipedia page and Wikipedia keeps page view statistics, a popularity can be inferred for each data point. I integrated this data by downloading three months of Wikipedia page view statistics,1 extracting the view counts, and associating a view count with each data point. Nugacious’ matching code was then modified to use a weighted average based on these counts for close matches and random matches; one non-weighted random match is still returned for each. Nugacious’ code is available on GitHub.


  1. This was ~190 GB.  

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Ubiquiti airFiber 5X Teardown

I recently came across a malfunctioning Ubiquiti airFiber 5X radio, so I decided to take it apart. The radio’s case can be opened by removing six T6 screws on the back. The PCB can then be removed by unscrewing six Phillips #1 screws, two of which are under the RF shields, and by removing the parts that secure the RF connectors to the case. The front part of the case is plastic, while the back part is aluminum; there is a gasket where the two case parts join and around the RF connectors. A polyimide film insulates the PCB from the aluminum case back.

Front Continue reading

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Camp Workcoeman Map App

Although I started mapping Camp Workcoeman years ago, I’ve always published this data as printed maps (and PDFs). I finally published my map in a different form: a mobile and web app. The apps are built using Mapbox GL, native for the Android app and JS for the web app.1 The Android version is completely offline, with the map data and style files bundled as assets. The full source code for both is available on GitHub. Download the app for Android or visit the web app (and add it to the home screen on iOS).

Camp Workcoeman Map


  1. Due to Apple’s developer fees and requirement to use OS X for development, there’s no native iOS version; I might reconsider this if there’s enough demand.  

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Climbing Cerro Toco

As a follow-up to my December climb of Lascar, I climbed Cerro Toco last week. The 5604 m tall dormant / extinct volcano is slightly taller than Lascar, but the climb has about half the vertical gain, so it’s easier. As I’m currently working on a telescope situated on the slopes of Toco, the climb was somewhat obligatory. The mountain, and the telescopes on it, is located within the Parque AstronĂ³mico Atacama. Leaving from San Pedro de Atacama, one gets to the trailhead by taking the Paso Jama road (CH 27) towards Argentina. There is then a turnoff for an unpaved road just after kilometer 35, which takes one up the mountain to the trailhead, which is located just past Toco’s three cosmology experiments. The trail is easily visible from the road. Driving past the trailhead allows one to see Toco’s abandoned sulfur mine.

Trailhead Continue reading

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