Mr.Linnolt wrote : > The formula you present seems to be a trigonometric > identity to my formula. Very good then. By the way, I did not know any formula was posted since the Email I happened to read suggested that no such formula had been posted. - birger To UNSUBSCRIBE from the 'meteorobs' email list, use the Web form at: http://www.tiacdot net/users/lewkaren/meteorobs/subscribe.html