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Time and Tide Wait for Gnomon By Roger Bailey NASS 2006 Vancouver.

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Presentation on theme: "Time and Tide Wait for Gnomon By Roger Bailey NASS 2006 Vancouver."— Presentation transcript:


2 Time and Tide Wait for Gnomon By Roger Bailey NASS 2006 Vancouver


4 Newcomers Tide Questions Tides are caused by the gravitational attraction of the sun and moon but…. Why are there sometimes two tides a day? Why are tides really high and low twice a month? Why are the really low tides in the middle of the night in the winter and midday in summer? Is there better information available than the newspaper tide tables? Can sundial science answer the Whys WHY?

5 Sundial Science: What Can You Learn from a Stick & Shadow Daily cycle of sun –Sunrise, sunset, noon –Time, Hours, Longitude Yearly cycle of Sun –Solstices, Equinox –Date, Declination, Latitude Monthly lunar cycle –Lunar Day ~25 hours –Phases, eclipses, obliquity –Saros cycle ~18 years Tides?

6 Moon Dials A sundial can be used as a moondial –When the moon is full –12 noon for the full moon is 12 midnight –Adding ~ 48 minutes for each day past full –Subtracting ~48 minutes for each day before full moon (actually 48 +/-7) Full moon declination ~ opposite sun +/- Exactly opposite for lunar eclipse Exactly equal for solar eclipse

7 Moon Madness: SML 1999 Proposed dual frequency harmonic sinusoidal tidal sensing correction system for a Moondial Daily tidal variation dampened Monthly tidal changes adjusted moondial hour angles Well Dampened Level Sensing Tidal Sea Patents Applied for: R. Bailey, R. Goldberg, H. Robinson

8 Aluna: Tidal Powered Moon Clock Imagine a breathtaking sculpture that combines cutting edge design and technology with an ancient knowledge of the Earth's natural rhythms. A monumental timepiece for the planet, a beacon for a sustainable future, reconnecting people with the Moon and tides. Proposed for UK & Australia

9 Aluna Time Wax & Wane ring –29.5 day lunar cycle Moons position, –rise & set –Lunar time Tidal Ebb & Flow –Alunas heartbeat –12:25 cycle –2:1 synchronicity with Lunar time Simplistic tide clock concept based on two high/low per day Does not show phase, latitude, or declination effects

10 Tides: Vancouver Aug 16-23 New Sun = Moon In Phase One Low / Day AM Solar

11 High (Spring) Tides Sun and Moon Effects New Moon Full Moon

12 Tides: Vancouver Aug 24-31 New Sun = Moon Out of Phase Two Weak Lows / Day

13 Sun and Moon Effects Quarter Moon Low (Neap) Tides

14 Tides: Vancouver Sept 4-11 Full One Low / Day Two Lows / Day

15 Harmonic Analysis: Equation of Time Sum of periodic changes to solar day Sum of obliquity and eccentricity effects Obliquity: –tilt of earths axis Eccentricity: – elliptical orbit

16 Harmonic Analysis: Tides Sum of waves of different amplitudes and periods – Sun: 24 hr day. 12 hr tides, Noon & Midnight 1 year, Solstice, Equinox, Declination – Moon: 24:48 hr day, 12.5 hr tides, monthly 29.5 day orbit, Phases, Declination Eclipses, Ecliptic, obliquity, Saros – RC resonance: velocity, volume, frequency – Phase shifts,Time delays, Shallow vs deep, funnel effects

17 Tide Tables: Hydrographic Surveys Click on and follow the links, maps etc for your location US Data: NOAA National Oceanographic and Atmospheric Agency UK Data: UKHO Admiralty Easy Tide $

18 NOAA Tide Graphic

19 Computing Tides on your PC Windows Tide and Current prediction program Install the free shareware on your PC Set up your preferences like your location It also includes locations for currents Based on NOAA Harmonic Analysis models and factors from world wide public sources Problems with use of UK harmonic factors and UKHO copyrights

20 Typical WXTides32 Screen Now Daytime Night

21 High Tides during day? Full Moon Latitude & Season Declination Effects Summer Phase shift to high tides at night! Tides lag behind gravity and water takes time to flow

22 Solstice Tides: Summer Negative Tides: Mid-day New Solar and Lunar Declination high Day (SUN) dominant Sun and Moon In phase

23 Latitude & Season Declination Effects Highest Tides at night for our northern latitude Full Moon Winter Phase shift to daytime high tides! Tides lag behind gravity and water takes time to flow

24 Solstice Tides: Winter 2006 New Solar and Lunar Declination low, in phase Night (MOON) dominant Negative Tides: Mid-night

25 Solstice Tides: Winter 2007 Solar Declination low, Lunar high Opposite but in phase Night (MOON) dominant Negative Tides: Mid-night Full

26 Time and Tide Wait for Gnomon Sundial (Stick and Shadow) science is useful for understanding tides Tides are caused by the harmonics of solar and lunar cycles Sundials show solar cycles, time of day, day of year, seasons and harmonics Moondials show lunar cycles Latitude and declination are important for shadows and tides Shadows and Tides

27 Time and Tide Wait for Gnomon By Roger Bailey NASS 2006 Vancouver

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