Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Celestial Sphere

  1. May 23, 2008 #1
    ok I know a bit about the celestial sphere and right ascension, declination, equinoxes, solistices, etc.

    What is the absolute origin in the celestial sphere?

    I know RA measurements use the vernal equinox, and that declination is +/- 90 degrees north/south of the celestial equator.

    I thought Polaris might be used as a fixed marker, but I also know precession means that Polaris is close to the NCP, but not exactly coincident with the NCP. Epochs and equinoxes are moments in time.

    So, what is used as an absolute marker of the celestial sphere from which all other markers, grids are derived?
     
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you help with the solution or looking for help too?
Draft saved Draft deleted