Name of projection to firmamentum (celestial sphere)

[DrDu]

TL;DR Summary

Does the central projection of the position of a star to the firmamentum (celestial sphere) has a special name?

Does the central projection of the position of a star to the firmamentum (celestial sphere) has a special name?

 

[tech99]

Celestial Position?

 

[phyzguy]

Celestial Coordinates? RA and Dec?

 

[DrDu]

There is orthogonal projection from space to the plane.
I thought of something like gnomonic projection, but this is from the sphere to a plane. I find it strange that the more obvious projection from space to a sphere has no proper name.

 

[phyzguy]

Normally when you take coordinates and project them down to a space with smaller dimension by just eliminating one coordinate, you just call it a "projection". That's what's being done here. I don't know that it needs a special name, since it's such a simple concept.

 

[DrDu]

Of course today we consider this trivial. But I thought that some medieval monks and arab sky mongers created thousand of strange names for it.

 

[phyzguy]

Of course today we consider this trivial. But I thought that some medieval monks and arab sky mongers created thousand of strange names for it.

It was way before that. Hipparchus created the first map of the celestial sphere in the second century BC.