Mr. Bob May and Mr. Ken, The url for "The Refractor Page" is http://www.cottrellweb.com/telescope.htm This was posted to the ATM list on 11 Feb 2001 under the heading ATM Lens Web Page according to the archives at: http://www.system.missouri.edu/atm Also according to the archives the above mentioned web page was mentioned in several post to the ATM list. Jim