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Cassini metadata: This year I spent some time doing the pleasant part of botmaking (ideation, data gathering) without the boring part (handling dozens of edge cases, signing up for accounts). One of the bots I never completed was "Cassini GIFs".

All the photos taken by the Cassini probe are online, and each photo has associated metadata. By looking for photos taken by the same instrument at evenly spaced times, you can find frames that would look good as an animation. Here's a nice example: a "movie" of Saturn's moon Dione taken on November 1, 2011:

It was really fun to make these animations that probably only a few people before me had seen. And the fun doesn't need to stop at Saturn: the SETI Project's OPUS3 has aggregated imagery from across NASA's outer planet missions.

The bad news for anyone else who wants to try this out is that the Cassini data is huge. You can download individual frames pretty easily, but the metadata is bundled in enormous tarballs and stored in an ad hoc 1990s file format. To provide a booster seat for the future, I converted the metadata into NDJSON format and put it up as cassini-metadata. Here's one more GIF to whet your interest: Saturn's rings on July 15, 2014:


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