Creating a Pluto flyby using unaligned New Horizons images | Hacker News Reader

Creating a Pluto flyby using unaligned New Horizons images

matthewearl.github.io

130 pointsmisiti378016 comments

Very fun project. I love these step-by-step descriptions of little code projects to see something fun.

For those wondering, Pluto and Charon orbit each other due to their Charon being 11.6% of Pluto's mass. So it's really a flyby of the center of their orbit.

Sorry to be pedantic, but all bodies in bound orbits do so around each other. Perhaps you meant that the center of mass of the Pluto-Charon system is outside Pluto's surface, so from afar they appear to be rotating around a point in space between the two bodies.

And as we are talking about it do both of them really just orbit around the sun, but the local gravity cause them to oscillation where one is closer to the sun before swapping? Locally it only looks like they are orbiting a spot in space?

Really, Pluto, Charon, and the Sun are all just orbiting Sagittarius A* , the center of our galaxy.

https://en.wikipedia.org/wiki/Sagittarius_A*

Very nice work! Wasn't the GIF I was expecting but that one is a simulation with the NASA images texture mapped on (https://vimeo.com/136223988).

I've been using ImageMagick to make GIFs recently and it's great. Only tricky bit is cropping. If anyone wants to pick up from the end of your article then I wrote up a guide on my blog: https://unop.uk/dev/make-animated-gifs-with-imagemagick

I can't tell from the writeup, is the animation speed a reasonably accurate analog of how fast New Horizons passed Pluto?

Each orbit of Pluto and Charon around each other takes 6.4 days. This is speeded up by a factor of a lot.

That makes more sense, I read quite a few articles emphasizing just how fast New Horizons was going so I got carried away.

The speed is relatively consistent except for the early frames (where pictures were taken at twice the rate of later on) and where frames were dropped due to missing data or alignment failure. Here's a version of the animation where frame duration is proportional to the real time between the frames:

http://i.imgur.com/ncTIdHL.gif

The animation spans 3 months or so. The real time is shown in the text in the corner.

Neat, thanks for sharing this!

Fixing your link:

http://i.imgur.com/ncTIdHL.gifv

Using ".gifv" in the link sends a video instead of a gif, way smaller file size and higher quality animations are better for everyone.

Very cool! I've forwarded this on to a few members of the NH software team

Excellent use of Python + OpenCV (one of my favorite 3rd party libraries)

Excellent! I hope to see myself and others use this for other probe flyby's... Thank you for opening up the source!

All that brilliance but they couldn't set the animation frame rate.

I skipped the variable frame rate out of this write-up in an attempt to keep things simple by leaving the GIF composing to an external program (ImageMagick). In an earlier iteration I did in fact create a version of the GIF with frame duration proportional to the real time:

http://i.imgur.com/ncTIdHL.gif

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