Nomogram Posted by sakuraiben on Sunday August 31, 2014 @01:02AM from the en.wikipedia.org dept. http://en.wikipedia.org/wiki/Nomogram ( 7 comments | 50 points | on HN )
The site also had a bunch of interesting information on analog computing in the context of spaceflight:http://www.projectrho.com/public_html/rocket/astrodeck.php
It's a great technique. Faster than a calculator or computer program, and satisfyingly physical too.
[1] https://en.wikipedia.org/wiki/Slide_rule