A BIFILAR DECLINING & INCLINED SUNDIAL (WITH NO-SINGULAR - PDF document

A BIFILAR DECLINING & INCLINED SUNDIAL (WITH NO-SINGULAR THREADS) Eric MERCIER Nantes (44)-France mercier-dupuis@wanadoo.fr «Commission des cadrans solaires-SAF» member -1-

-2-

In 1922, Professor Hugo Michnik, invented the bifilar sundial. In the original version, the bifilar sundial has two non-touching threads parallel to the horizontal dial. The second thread is orthogonal to the first. The intersection of the two threads' shadows gives the local apparent time. Michnick’s bifilar sundial (Wikipedia) In sundial proposed here, the table is declinining and inclined, and threads are no- parallel to the table and no-perpendicular each other. The threads The table no-singular positions declining & inclined -3-

This dial is designed with an original software (HUGO 1 ) described in two papers published in "Cadran-Info" ( co-author: Dominique Colin ). Download : http://studios-nantes.pagesperso-orange.fr/Gnomonique_files/M.E_C.D_Logiciel %20bi%20filaire.pdf http://studios-nantes.pagesperso-orange.fr/Gnomonique_files/M.E_C.D_Logiciel %20HUGO.pdf Note : The software version used here is newer and better than the one described in papers because it takes into account the threads length. Software output: grey lines are hour lines position in the case of threads became longer. 1 in homage to Professor Hugo Michnik. -4-

The sundial table -5-

October 11, 11h30 (TU+2) threads shadows in red October 12, 12h00 (TU+2) threads shadows in red October 12, 13h00 (TU+2) threads shadows in red No cross ! -6-

October 11, 15h00 (TU+2) threads shadows in red Cross is back !! October 12, 16h00 (TU+2) threads shadows in red October 12, 17h00 (TU+2) threads shadows in red Sorry, no more sun in this place, in October ! -7-