Error Analysis of a Monumental Garden Variety Sundial

Error Analysis of a Monumental Garden Variety Sundial Roger Bailey NASS 2009 Portland, OR ©Phil Palies

Questions for NASS Registrar Artist’s rendering from website http: //www. soaplakememorialstones. com Is this a Sundial? • How do I register this sundial? • Now under construction at Soap Lake WA • Is there a sundial expert we can consult?

Response from NASS “Expert” Artist’s rendering from website http: //www. soaplakememorialstones. com • A sundial is an instrument designed to tell time • The gnomon must be straight and at the correct angle • The hour lines depend on the location and are different for each hour. • What is now cast in bronze & cement? Data & pictures required On angles, size, location, etc

Hour Lines for 47. 4º Latitude

Hour Lines for 47. 4º Latitude

Hour Lines for 37º Latitude

Shadow Lengths through the Seasons

Orientation • Use the sun’s shadow to determine the orientation • Table of times when the sun is south, east or west • Spreadsheet corrected for EQT and Longitude Date DOY Declination EQT º Noon South 16 -May-2009 135 19. 20 3. 6 0. 910 12: 54: 19 17 -May-2009 136 19. 42 3. 6 0. 903 12: 54: 20 18 -May-2009 137 19. 64 3. 6 0. 894 12: 54: 23 19 -May-2009 138 19. 86 3. 5 0. 882 12: 54: 25 20 -May-2009 139 20. 06 3. 5 0. 868 12: 54: 29 21 -May-2009 140 20. 27 3. 4 0. 851 12: 54: 33 22 -May-2009 141 20. 47 3. 3 0. 833 12: 54: 37 23 -May-2009 142 20. 66 3. 2 0. 812 12: 54: 42 24 -May-2009 143 20. 84 3. 2 0. 789 12: 54: 48 25 -May-2009 144 21. 02 3. 1 0. 765 12: 54 26 -May-2009 145 21. 20 3. 0 0. 738 12: 55: 00 Sun West 17: 39: 36 17: 38: 39 17: 37: 43 17: 36: 49 17: 35: 57 17: 35: 07 17: 34: 19 17: 33: 32 17: 32: 48 17: 32: 05 17: 31: 24 Sun East 8: 09: 01 8: 10: 02 8: 11: 02 8: 12: 02 8: 13: 00 8: 13: 58 8: 14: 56 8: 15: 52 8: 16: 48 8: 17: 42 8: 18: 36

Soap Lake, WA Mineral Milligrams/Liter Sodium 5760 Bicarbonate 2480 Sulfate 2540 Carbonate 3840 Chloride 2290 Potassium 504 Organic nitrogen 0. 9 Fluoride 7. 2 Ortho-phosphate 6. 3 Nitrate 0. 7 Calcium 2. 5 Magnesium 2. 9

Soap Lake Garden Club

Healing Waters • Spa treatment like thermal mineral baths in Europe • Bathing in the alkali waters, soaking in the mud, cures people afflicted with Buerger's disease and other ailments [ www. geocaching. com GC 1 DJWD

Modern Spa Treatment • Spa treatment is now an sensual indulgent luxury • ‘You deserve it” • Hot rocks • Hot oil massage • Aromatherapy • Soap Lake missed the market • “Calling the healing Waters” a new focus

Concept • Centre of Interest for Soap Lake • Build it and they will come • Theme: Calling the healing waters • Reflects ethnic and historical themes • Mighty winger warrior protecting and comforting maiden with catch basin for healing waters

Installation of basalt columns Angles and offsets are obvious

Error Analysis • Sculpture is a poor sundial • A worst case scenario • Feathered arm at ~37º but curved and offset from center • Base at ~30º is offset vertically • Various parts of the structure cast shadows on the hour lines on the base

Error Analysis

• Users: Error Minimazation Considerations – People going to the park to enjoy the beach and water. – Good time not regimented time • Season: – Summer not winter – Spring and fall if the weather is good • Time – 9 AM to 5 PM Summer – Peak mid-afternoon • Impression: – Form follows fashion, not function – Looking good is most important

Sundial Considerations • Can the sundial work? – – giving an impression of time When most people will see it • Design for summer, solar noon +/- four hours • Design based on a point gnomon, the tip of the feather • Calculate design for 47º – Hold the gnomon tip fixed – Move the base intersection to 37º design • Calculate shadow planes for 37º at various times of day and declinations of the year • Choose the best compromise considering use • Design is fit for purpose

Shadow Plane Analysis • The 37º gnomon has a shadow plane • Shadow plane intersects the base at a specific angle • Shadow angle (SA) varies through the seasons • Tan SA= Sin G x Sin Az/ Cos G x Tan Alt +Cos G x Cos Az – – giving an impression of time When most people will see it • Spreadsheet used to calculate altitude, azimith and the declination, latitude and time angle • Sin Alt = Sin Dec x Sin Lat + Cos Dec x Cos Lat x Cos t • Shadow angle calculated from altitude, azimuth and gnomon angle • Plotted on sundial design by Zon 2000 with Delta. Cad • "Error Analysis of The Horizontal Sundial-I" Lauoesch & Edinger, NASS Compendium 2 -3, Sept 95

Shadow Plane Analysis

Artists • David Govedere Sculptor • Keith Powell Artist • Concept accepted in 1994 • Bronze sculpture cast in 2003 ©Phil Palies

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Finished Sculpture • Curved offset feathered arm as gnomon • Hour Lines and Posts • Solar Noon +/four hours • 9 AM to 5 PM © Raymond Gravelle

Time Check XII • XII is XI solar • Hour Line band = post widths • Tip of shadow in the middle of hour band • Curve and offset of feathered arm is obvious • Time check OK © Raymond Gravelle

Time Check III • III solar II • Again the tip of the feathered arm tells the time • Hour lines diverging • Time check OK © Raymond Gravelle

Summary • Objectives met • Sculpture looks good, an excellent focal point on the Soap Lake beach • Sundial is fit for purpose • Time indications OK in the summer 9 AM to 5 PM © Raymond Gravelle

Toolbox • NASS Compendium & Presentations • “Error Analysis of The Horizontal Sundial" Lauoesch & Edinger • “Error Analysis of Garden Variety Sundials” • Software: Zon 2000, Delta. Cad, Excel • Spreadsheets: • Error Analysis Garden Variety Sundials • Shadow Angles • Meridians and Prime Vertical

Acknowledgements • Raymond Gravelle: Challenge, data, photographs, patience • Larry Mc. David: Asking the right questions • Phil Palios “Philthy Photography” Photos of the dedication ceremony at http: //www. flickr. com/photos/philthy_photography/sets/72157620424323215/