Hello Nicolas, Thanks for making the IGBs available directly from your web site. The Yahoo system was not very easy to use. I very much enjoy reading the bulletins.
I was interested in the quadrant and ring at St John's College shown in the latest International Gnomonic Bulletin 07. The equatorial ring has a long history. It is this type of ring that the Greek astronomers used to precisely determine the time of the equinox. From these equinox timings Hipparchus about 130 BC was able to determine the precession of the earth's axis of rotation. I would love to have access to such a ring to see the equinox shadow as the declination of the sun changes rapidly ~24'/day. There were a few minor errors in the article. The link no longer works. Try http://www.stjohnscollege.edu/asp/main.aspx?page=6591&parent=1106#quad . This will bring up the new page showing the ring but the picture is no longer in colour. The IGB article places the quadrant and ring in Santa Fe but they are at the St. John's campus in Annapolis. Regards, Roger Bailey N 48.6 W 123.4 -
