Re: Equatorial monument in Brazil

[DrArthurCarlson]

Hold still, I think I see a nit!

The rate of change of the declination at the equinoxes is 24 arc-minutes per day, approximately equal to the size of the image of the solar disk, so if the spot is perfectly centered on the line at dawn, by dusk it should be nearly off one side.  Actually, this is cool, because it means with appropriate and painstaking observations you can determine the moment of the equinox to within a few hours.

Art Carlson