Data: Stellar Quadrant Observations – 9/22/18 (Crucible at the Crossroads)

This weekend was Crucible at the Crossroads here in my home Barony of Three Rivers. I taught two classes, one on a general overview of medieval astronomy, and one introducing practical observational astronomy. In addition, it was the autumnal equinox on Saturday, so some minor adjustments were made to the quadrant to allow for solar angle observations. Lastly, I was called up in court for a few awards related to the project.

More on all of that beneath the fold. Continue reading “Data: Stellar Quadrant Observations – 9/22/18 (Crucible at the Crossroads)”

Almagest Book II: Symmetry of Rising Times – Arcs of the Ecliptic Equidistant from the Same Equinox

In this next chapter, Ptolemy’s goal is to

show how to calculate, for each latitude, the arcs of the equator… which rise together with [given] arcs of the ecliptic.

To do this, we’ll do a bit of convenient math, breaking the full ecliptic into its traditional 12 parts. However, since these signs are not of equal size, Ptolemy takes an even 30ยบ for each sign, beginning with Aries, then Taurus, etc…

The first goal will be to prove that

arcs of the ecliptic which are equidistant from the same equinox always rise with equal arcs of the equator.

Continue reading “Almagest Book II: Symmetry of Rising Times – Arcs of the Ecliptic Equidistant from the Same Equinox”