What is the diameter of the Celestial Sphere?
1 Answer
May 8, 2016
Arbitrarily large, with a minimum size sufficient to account for the unobservable stellar parallax of most stars.
Explanation:
The Celestial Sphere is an imaginary sphere centred on the sun of arbitrarily large radius on the surface which the stars are supposed to be while the planets (wanderers) orbit the sun within it.
The size of the sphere needs to be large enough that stellar parallax is not discernable to an ordinary observer.
I guess a light year or two would be sufficient.
As an accurate model of the universe this is thoroughly debunked, but it can be useful for such purposes as navigation, etc.
