Name of projection to firmamentum (celestial sphere)

  • Context: High School 
  • Thread starter Thread starter DrDu
  • Start date Start date
  • Tags Tags
    Projection Sphere
Click For Summary
SUMMARY

The central projection of a star's position onto the firmamentum, or celestial sphere, does not have a widely recognized specific name. Terms such as "Celestial Position," "Celestial Coordinates," and "RA and Dec" are often used, but they do not denote a unique projection method. The discussion highlights that while gnomonic projection refers to projecting from a sphere to a plane, the reverse projection from space to a sphere lacks a distinct terminology. Historical context is provided, noting that Hipparchus created the first celestial sphere map in the second century BC.

PREREQUISITES
  • Understanding of celestial coordinates, specifically Right Ascension (RA) and Declination (Dec).
  • Familiarity with projection methods, including gnomonic projection.
  • Knowledge of historical astronomy, particularly contributions from figures like Hipparchus.
  • Basic concepts of dimensionality in geometry and projections.
NEXT STEPS
  • Research the historical significance of Hipparchus's celestial sphere map.
  • Explore various projection methods in astronomy, focusing on their applications and limitations.
  • Investigate the terminology used in celestial navigation and mapping.
  • Learn about modern celestial coordinate systems and their relevance in astrophysics.
USEFUL FOR

Astronomers, historians of science, educators in astronomy, and anyone interested in celestial mapping and projection techniques.

DrDu
Science Advisor
Messages
6,423
Reaction score
1,004
TL;DR
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?
 
Last edited:
Astronomy news on Phys.org
Celestial Position?
 
Celestial Coordinates? RA and Dec?
 
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.
 
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.
 
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.
 
DrDu said:
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.
 

Similar threads

Graduate Trouble visualizing and understanding the celestial sphere
  • · Replies 7 ·
Replies
7
Views
3K
High School Contradictions in the Distribution of Gamma-Ray Bursts
  • · Replies 24 ·
Replies
24
Views
1K
High School Night Sky of Alpha Centauri: Sol as a Bright Star
  • · Replies 15 ·
Replies
15
Views
4K
High School Why does the moon appear tilted?
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Celestial sphere and visible stars
  • · Replies 6 ·
Replies
6
Views
5K
High School How black hole Sgr-A* Was Found
  • · Replies 1 ·
Replies
1
Views
2K
High School Can someone explain thoroughly the celestial sphere
  • · Replies 8 ·
Replies
8
Views
5K
High School How can the Universe be flat? Ridiculous
  • · Replies 13 ·
Replies
13
Views
4K
High School Why isn't there an effort to name non-stellar celestial objects?
  • · Replies 21 ·
Replies
21
Views
3K
High School The configuration of galaxies in space
  • · Replies 4 ·
Replies
4
Views
2K