Sunday, March 09, 2008

The Planetarium Cone

Like the Louvre Pyramid, I like it when old and new clash in architecture. Behind the Greenwich observatory, in the same grounds, is the Peter Harrison Planetarium where they have erected a bronze cone with the following characteristics:

  • The north side of the cone is aligned with the point in the sky perpendicular to the Greenwich local horizon (zenith)
  • The sloping southern side points towards the north celestial pole (Pole star). The angle of the slope is 51º28'44", equal to the latitude of the Royal Observatory
  • The top of the cone is sliced at an angle parallel to the celestial equator
  • The planetarium is aligned with the local meridian (north-south line)

I think it is pretty cool too :-)

Camera: Pentax MZ-3, lens: Sigma 24-70mm F2.8 EX DG MACRO