I built Zenith: a live local-first fixed viewport planetarium
This is a real time view of the stars above you right now. The stars move faster than you’ve seen before because the view is zoomed in. Zooming in not only makes things look bigger, it also makes motion appear faster. This is not time lapse, or sped up. The motion you see is only due to the earth’s rotation.
If you’ve ever tracked something moving on a map, like a delivery, you may have zoomed in to get detail of its motion.
Zooming in gives more detail and faster motion, but shows less surrounding context.
Photography and computer displays use the term “zoom”. With telescopes it’s “Field of View” or “magnification”. It’s the same concept. Tiny field of view = higher magnification = zoomed in. The magnification is about 180x
The goal of this project: zoom in enough so that the amount a star moves in 30 seconds would span the screen, this would make the turning of the earth visible. Therefore I defined the field of view as the amount the sky turns in 30 seconds.
That Field of view turns out to be a patch of sky the size of a grain of rice, held at arm’s length.