hobby #222

Planispheric Astrolabe Construction and Star-Timekeeping

Laying out and engraving a working brass planispheric astrolabe — the rete, the latitude-specific tympan plates, and the alidade — then using it to sight a star's altitude and read off the time of night, sunrise, or your latitude. A hand-built analog computer of the sky that you both draught and observe with.

Forty Minutes Wrong Because I Trusted the Star

I already owned this latitude, so I flattened the whole sky onto paper — then hung it from one thumb, sighted a star, and confidently read a time forty minutes wrong.

code-a-day tied to this hobby

Rotating a Vector to Find a Star's Angle CORDIC algorithm

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