Saturday was tour day, starting at the Kitt Peak National Observatory, an hour’s drive from Tucson. Kitt Peak is home to the world's largest collection of optical telescopes. Located high above the Sonoran Desert, Kitt Peak presently has twenty-two optical and two radio telescopes and offers astronomers some of the finest observing to be found in the world. Here we had a special guided tour of the famous McMath-Pierce Solar Telescope Facility, the 7m Solar Vacuum Telescope and the Mayall 4m Telescope.  The McMath-Pierce Solar Telescope At the solar telescope we observed the sundial time scales laid out by John Carmichael and Bob Hough. Key to accuracy was the use of shadow sharpeners to fix the center of the solar shadow. The picture on the right was taken at the time of the style shift when the shadow moved from one edge of the gnomon to another. |
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Below left, Fred Sawyer points out the features of Robert N. Mayall’s equatorial sundial to Fritz Stumpges and Bill Walton
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We then went back to Tucson for lunch at Tohono Chul Park, a beautiful desert botanical park. Here John Carmichael showed us his 53" Horizontal Sundial. |
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John points out some of the features of his dial to Carl Haskett, Fred Sawyer and Claude Hartman. |
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We then went on to the Nanini Sundial, a large metal south wall vertical dial with adjustable time scale, built in 1987. The designer is unknown. This group picture is by Carl Trost.  |
 Next on the tour was the Sun Circle, a large 50 ft. Stonehenge type sun ring built from colored cement blocks and flagstone. The artist Chris Tanz explained its design and interesting history. |
The inspiration for the Sun Circle comes from recent discoveries about the ceremonial life of one of the great native cultures of the Southwest, the Anasazi, who lived in Arizona and New Mexico a thousand years ago. The structure consists of eight interrupted curving walls which together imply a circle. Six of the wall segments have small ports oriented toward sunrise and sunset at summer solstice, winter solstice, and the spring and fall equinoxes. At sunrise on the critical days, light pierces through the sunrise wall and projects its window on the facing wall (the height of the Image determined by the height of the horizon). At sunset, light comes through the sunset window, tracks along the floor and up the facing wall, projecting an image of the window that climbs toward its matching window and winks out as the sun dips below the horizon. Every day, solar noon is marked when sunlight coming through the slot in the South wall lines up with the track on the floor.
Then John Carmichael invited us into his studio to see several of his finished dials and other sundials under construction. Here John is demonstrating his design and stone carving techniques. |
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Below is a Tabletop Analemmatic Dial that John recently completed. Note that it incorporates the “Seasonal Sun Rise and Set Markers”. |
Following refreshments and the demonstration at the Carmichael Studio we moved on to the last stop on the tour, the Flandrau Planetarium to see John’s large Horizontal Monofilar Heliochronometer. Here Fred Sawyer was interviewed by a reporter.
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The Flandrau planetarium also has a “Sidewalk Sundial”, an interactive analemmatic sundial where this passing U of A student was persuaded to check the time indicated by her shadow. John Carmichael and Robert Hough have recommended changes to this dial to remove some errors in the current design. The final dial was a classical horizontal dial at the Stewart Observatory across the road from the Flandrau Planetarium.
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Return to the Conference on Sunday Morning