Where do the symbols $\lambda$ and $\beta$ come from for celestial latitude and longitude? I'm reading Episodes From the Early History of Astronomy, and the author mentions the system of celestial coordinates based on the ecliptic. In this system, the two coordinates are latitude and longitude, denoted by $\lambda$ and $\beta$. Where does this choice of symbols come from?
$\lambda$ is &quot;l&quot; like in &quot;latitude&quot;, I guess. But why $\beta$?
German: $\lambda$ (or l) like Länge (longitude) und $\beta$ (or b) like Breite (lattitude). A century ago it used to be a language many science papers were published in and English was far from dominant.
Mind though that it is just symbols of notation and you can define them as you see fit - if you define them. They are just one choice among many possible and one among a few commonly used, depending a bit on context where you come from.