of coordinates bound to an inclined sundial of given declination are: where: : declination of the plane of the sundial : inclination of the sundial, that is, the angle of the normal with respect to the zenith Other uses Gnomonic projection is a map projection where the vanishing point is in the centre of a spheroid. References Sources External links at the Société Astronomique de France website , Minutes of meetings of the Commission des Cadrans solaires du Québec (CCSQ) from 1995 to 2014, available as PDF files In May 2018, a French-language was launched by a member of the Sundials Commission of the Société astronomique de France. Sundials