Alas, the fleeting years glide away, Postumus, Postumus!
-- from "Eheu fugaces", an ode to Postumus on the futility of hoarding up treasure
Read this only if you have nothing else to do but note down the angle subtended by the sun (or the moon) at your eye every two minutes.
This blog has no copyright. So, with respect to anything you find here, you are free to reproduce, distribute, interpret, misinterpret, distort, garble, do what you like, even claim authorship, without my consent or the permission of anybody.