Zarbula’s Sundials

1. Zarbula’s Sundials Roger Bailey & Alain Ferreira NASS 2005 Chicago

2. Sundials in France Distribution by Département Hautes-Alpes 772 Highest sundial density in the world! Ref: http://www.saf-lastronomie.com/cadrans/carte_2002.gif

3. Why Hautes-Alpes? • Alpine folk art traditions • Insolation: 330 days of sunshine • Isolation from politics and progress • Travel over the passes not down the valleys • Transhumance- summer alps, winter Piedmont • Independent Republics • Five “Escartons de Briançonnais” • from 1343 until 1713 and 1789 • Itinerants: shepherds and tradesmen

4. ZARBULA ZONE Alpine Sundials Bavaria Austria Engadine Tyrol France Italy

5. Sundials of Giovanni Francesco ZARBULA

6. Who was Giovanni Francesco Zarbula? • We only know his name and his works • Itinerant Italian painter • Piedmont to Hautes Alpes • Only tools, materials and techniques that could be carried by a donkey • Speciality: bold flamboyant vertical declining sundials • Distinctive folk art style • Accurate gnomonic method • Long lasting fresco paintings

7. Zarbula’s StyleBaroque Italian Folk Art • Equinoctial Line • Birds and Flowers • Frame, curtains, tassels • Sun and crescent moon • Symbols: Masonic and Religious • Mottos: Latin, French, Italian, Provencal • Signed: GFZ or ZGF • Dated: 1830 – 1876 • Maljasset, Ubaye, 1860

8. ZARBULA ZONE

9. 95 Zarbula sundials 26 ORIGINALS 11 WITH ZARBULA’s DRAWINGS 36 RESTORED 23 PHOTOS FROM ORIGINALS 33 LOST 5 PHOTOS OR DRAWINGS OF THOSE LOST 5 DUBIOUS 8 DUPLICATES OR COMPLEMENTARY

10. 2 VALLOIRE Italy, Piedmont Zone Val Chisone Latitude 45º VALLEE DE LA CLAREE 20 sundials ZONE BRIANCON 4 29 VALLOUISE 4 NORTH ZARBULA ZONE

11. ZARBULA’ s Method Discovered by Paul Gagnaire, From the Valloire sundial, at Les Verneys en Savoie. Ref : Cadrans solaires en Savoie, 1999 by P.Gagnaire. Page 130-137: A Valloire, Solved mystery. L’Equere et L’Oiseau ou L’Art et La Maniere de ZARBULA by P.Gagnaire. 2000 Cadran Info SaF http://www.ens-lyon.fr/RELIE/Cadrans/Promenades/Zarbula/Equerre.htm

12. ZARBULA’ s Method Les Verneys en Savoie. Drawing by P.Gagnaire

13. 6 o’clock Horizontal Equatorial Equatorial Circle Noon Zarbula’s Construction Lines

15. Zarbula’s Method: The Sun Rules! Zarbula did not need to know the latitude or wall declination to define the dial. The shadow determined the sub-style line Zarbula used no calculations or tables. Simple geometry determined the hour lines. Zarbula worked at the latitude of 45° None of the sundials are oriented North. The wall is vertical and declining from south. Zarbula already knew the sundial’s size and location on the wall.

16. Principle 1: Horizontal Equivalence • AnyVertical Declining sundial has a equivalent horizontal sundial at in the southern hemisphere at a different latitude • Determine the sub-style distance and sub-style height for the polar axis • Lay out the hourlines for the horizontal equivalent

17. He drives in a horizontal style at C perpendicular to the wall C XII He draws the vertical noon line XII and marks the centre C Zarbula’s Method

18. C XII Principle 2: Indian or Hindu Circle for Sub-style Zarbula draws point by point a hyperbolic declination line, representing of the path of the tip of the shadow.

19. P 2 P 1 S Zarbula draws the sub-style, the axis of symmetry of the dial Zarbula’s Method C XII

20. Center of sundial C SUB-STYLE S Zarbula’s Method NOON LINE XII XII

21. 45° 45° M ’ M S Zarbula’s Method The perpendicular gnomon gives the shadow path to set the sub-style line. For the actual dial, polar style is from the intersection of the noon meridian and the same sub-style line. C

22. Principle 3: Rotation of the Meridian Plane C • Meridian plane shows the Latitude , Co-Latitude, Polar style and Equatorial true size • Rotation of the Meridian plane about the Meridian axis to the Sub-style, perpendicular to the wall, shows the Substyle Height • Rotation defines the Equatorial Horizon plane Polar Style Co-Lat Lat Equatorial Noon

23. C 45° 45° 45° Noon to equinox M Zarbula’s Method Define the Equatorial Horizon by rotating the meridian plane and the latitude angle around the vertical Meridian axis

24. Horizon Zarbula’s Method C 45° He draws a horizontal line 45° 45° M S

25. Equatorial Zarbula’s Method C 45° Horizon 45° He draws an equatorial line perpendicular to the sub-style line M S

26. Zarbula’s Method He draws the 6 o’clock (18h) line to the equatorial horizon C 18h Horizon Equatorial M S

27. Equatorial S Zarbula’s Method C If it’s morning declining, he draws the 6 am line 6h Horizon M

28. 48° 18h 42° Equatorial Generalised method for different latitudes Zarbula’s Method C Example Chicago = 42° Horizontal line M S

29. 18h O ? ? ? 12h W Zarbula’s Method C Horizon Equatorial Zarbula draws the center W of an auxiliary equatorial M S

30. Principle 4: Always 90º between noon and 6 o’clock Vertical méridional sundial Villevieille church, Queyras

31. Zarbula’s Method C 18h Horizontal line Starting from auxiliary equatorial centre W, he draws the 15° angles to the equatorial line R 12h Sub-Style Height is RW, radius of the auxiliary equatorial circle Equatorial M W S

32. 19h 17h 16h 15h 14h 13h 11h 10h 9h Zarbula’s Method C The intersections are numbered in sequence from noon to 18 o clock Horizon line 18h 12h Equatorial M W S

33. Zarbula’s Method The only thing left is to draw the hours lines from C point... C 19h Horizon line 18h 17h 16h 15h 14h 13h 11h 10h M Equatorial S 9h

34. Zarbula’s Method Installation of the Polar Style (Gnomon) above the Sub-Style Line C 19h Horizontal Line 18h 17h 16h 15h 14h 13h Sub-Style Height is the Radius of the auxillary equatorial circle 11h 10h M Equatorial S 9h

35. Principles of Zarbula’s Method • Horizontal Equivalence of Vertical Decliner • Indian (Hindu) Circle for sub-style line • Meridian plane contains Latitude true size • Rotate Meridian plane to establish Horizon plane Equatorial line and 6 o’clock line • 90º between Noon and 6 o’clock • Equatorial Tangent line for hour lines and Sub-style Height • The geometry is correct; the method is accurate, within some limitations

36. Test of Zarbula’s Method 1. Sub-style line Latitude: 48.6º N Declination: 58º E Shadow Path for 14 June

37. Test of Zarbula’s Method 2. Equatorial Tangent Line DeltaCAD design drawing using Zarbula’s Method gives identical results to trig calculations

38. Zarbula’s ToolsSticks and String • Sticks • ruler, straight edge • set square 45º & 90º • compass, dividers • gnomon • String • plumb bob • chalk line • compass

39. Zarbula’s Painting • Fresco techniqueon parged masonry walls • Mineral oxide pigments on fresh lime mortar • No organic materials • Weather and sun resistant • Quick bold strokes

40. Ochre de Provence Pigments : Ochre (iron oxides) for yellow orange &, red. black soot, zinc oxide white, cobalt blue, copper greens Sienne earths.

41. QUEYRAS 38 sundials UBAYE 2 LES ORRES LES TANCS 1 1 ZONE ZARBULA South

42. Château Queyras

43. QUEYRAS 3 CERVIERES ABRIES ARVIEUX CHÂTEAU QUEYRAS 4 1 7 AIGUILLES 12 LES ESCOYERES 2 MOLINES 7 SAINT VERAN 2 EYGLIERS

44. First Known Zarbula Dial Queyras, Arvieux, le Coin

46. 1832 QUEYRAS Arvieux, Les Escoyères

47. VI HORIZON EQUATORIAL

48. Original Restored by Evelyne and Norbert Peyrot 2000 1839 Cervières, Customs Office

50. 18?? QUEYRAS Château Villevieille Clot du Riou