Sundials - World's Oldest Clocks

# North American Sundial Society

## Features

This Sundials for Starters appeared in The Compendium in December 2013

Robert L. Kellogg, Ph.D.

 Fig. 1 Analemma over the Acropolis photographed during the year by Ayiomamitis

As the shadows grow longer and we head for the winter solstice my mind turns again to the analemma, a concept invented by Grandjean de Fouchy in 1740 to describe the apparent irregular motion of the sun. Strictly speaking, this is the difference between the right ascension of the true sun minus the right ascension of the mean sun. While this is mathematically important to astronomers, it is esthetically pleasing that the apparent sun will describe a “figure 8” through annual motion in the sky. This “figure 8” or analemma is visible only when the sun’s position is compared to a “mean time” using a precise clock. The analemma (or the sun’s apparent East-West motion called the Equation of Time) allows us to answer the question “Will the time shown on my sundial be fast or slow compared with my watch?”

He may be wheelchair bound, but that doesn't diminish Tom Laidlaw's enthusiasim for sundials.  In front of his house on Carolina Lane is the Vancouver Heights neighborhood landmark - a sundial garden.  And what has he planted?

There is a bright circular equatorial sundial that shows the time from 4am to 8pm (and even an offset for daylight saving time).  On the grass is an analemmatic sundial sundial marking time from 6am to 6pm for anyone who wants to stand to the plywood walkway.  On a table near the house are a series of globe, equatorial and horizontal sundials as well as other sundial types that he will gladly explain.  For example, Tom has turned a skate board into a polar dial by adding a "T" gnomon in the middle.  And then there is a model of the Jefferson dial where you swing the gnomon around a globe to cast only a thin line shadow

Katie Gillespie, of the Columbian, reports "The 80-year-old retired electrician has always been a 'do-it-yourself kind of guy,' he said. For a while, it was skateboards he fancied, and bookshelves, and a Benjamin Franklin chair that transforms from a chair into a stepladder. He’s self-taught, he said, researching new projects online, then diving in.... 'It’s fun to watch him talk to people about it,' said Debra Brouhard, Laidlaw’s daughter and neighbor."

His latest obsession is sundials.  As a member of the North American Sundial Society, Tom now designs a multitude of sundials.  Visitors see his yard dotted with all types of sundials.  They come in all sizes: big and small.  His analemmatic sundial on the lawn always draws attention. Nearby, a plumb bob dangles from a beam. allowing Tom to tell time solar noon. when the shadow draws a line on the lawn pointing due north.

Gillespie found that, "Laidlaw’s passion for sundials began in 2009, when his grandson, Doug Brouhard, stuck a stick in the ground while they were camping. Doug Brouhard was about 12 at the time, and the dial didn’t quite work, Laidlaw said. It was the right idea, though, and a new hobby was born. 'I still have the stick that started it all,' Doug Brouhard said."

Read more of Katie Gillespie's article and see more photos of Tom Laidlaw and his sundials at http://www.columbian.com/news/2017/aug/30/sundial-garden-shines-in-vancouver-heights/

One of the highlights of the NASS conference in St. Louis was the 3D printed Schmoyer Sunquest civil time dial rendered by Bob Kellogg and featured in the NASS Compendium.  Following a video on his 3D printing process, NASS gave away 3 dials he had donated.  That left a roomfujl of people wondering how they could get one!

Since that time, Bob has made a number of tweaks to the design - including provisions for a dial in the Southern hemisphere and adding a knob to move the gnomon precisely for the weeks around the solstice where the gnomon Equation of Time has been stretched

The Schmoyer Sunquest is a 3D printed 1/3 - scale plastic version (5 1/2" diam.) of Schmoyer's original  design.  It comes as a kit that is easily assembled and adjusted for your location with a Phillips-head screwdriver and about 5 minutes of your time.  Full instructions are included.

So now it's time to make the dials gernerally available.  We are happy to announce that you can now purchase the Schmoyer Sunquest from NASS (all profits will benefit NASS goals of education and fostering dialing projects and the art of gnomonics as a 501(3)c not for profit organization).  Bob has volunteered to provide the society with a supply to meet the demand.  But note that he can only print about 1 dial per day! -  so get your order in.

Price: \$35 US dollars each plus s/h

 Shipping/Handling (s/h) in: US \$7 for 1-2 dials Canada/Mexico \$25 for 1-2 dials Elsewhere \$34 for 1-2 dials

Please make your U.S. dollar denominated check (drawn on a U.S. bank) payable to NASS.  Provide your mailing address information and send payment to:

Fred Sawyer, 27 Ninas Way, Manchester CT 06040 USA

Alternatively, you can use PayPal to send payment to This email address is being protected from spambots. You need JavaScript enabled to view it.. (Note: Payments from outside the U.S. can be made in U.S. dolars via PayPal.  PayPal will do the currency conversion for you.)

All requests will be filled in the order in which payment is received.  If you want a dial for the Southern hemisphere or the original "classic" Schmoyer Sunquest dial without adjustment knob, you must let us know at the time you order the dial.

The North American Sundial Society held their annual sundial conference in Pittsburgh, a four day affair for gnomonists to convene and share their enthusiasm for all things sundials.  This conference was special as the NASS celebrated the society's 25th anniversary.  Starting in 1993 with only a handful of dialing enthusiasts, the society has grown to over 250 members extending from North America to all parts of the globe.  For this conference NASS members convened from around the world representing countries of Canada, the United Kingdom, Brazil and Australia.  Scheduled to attend but intervened by last minute issues preventing their attendance were dialists from Mexico and Italy.  All came with one objective - to share their enthusiasm for sundials.

On Thursday evening Aug 16th the dialists gathered at the Garden Hilton in downtown Pittsburgh to participate in drawings for assorted door prizes including sundials and books on dialing.  On Friday all boarded a charter bus to view the sundials of Pittsburgh, taking a tour that included a large steel equatorial designed and built by Anthony Vitale, a multi-faced dial at Old Economy Village dating to 1825, and a dial commemorating the battle at Bushy Run in 1793 that was found at the site of the Fort Pitt Block House during its 1894 restoration by the Pittsburgh Chapter of the Daughters of the American Revolution who still own and preserve the structure and the sundial. The tour included the dial at Frick Fine Arts Museum (near the geenhouse), the Riverfron Park Sewickley analemmatic (human) sundial, and the large octagonal horizontal sundial at Homewood Cemetery.

On Saturday and Sunday attendees listed to presentations on ring dials (with a diverson into the history of solving cubic equations), helical sundials (and 3D printing), viking sunstones (with a description of the birefracting material calcite), lunar sundials (Sciathericum Seleniacum), van Schooten and Dialing Scales (published in 1657), Time for Rita's (a vertical declining dial designed for an ice cream store in Elizabethtown, PA), and zenith days below the Tropic of Capricorn (and a year-long photograph of the analemma over the El Cerrito pyramid in Querétaro, Mexico),and much, much more.  On Saturday evening the Sawyer Dialing Prize was awarded this year to Gianpiero Casalegno from Italy for his achievements in harnessing modern ditital technology to the benefit of tradional dialists around the world.  The prize includes an elegant Spectra Sundial by Artisan Industrials (Jim Tallman) and a cash award.  Gian has chosen to given the cash award as a donation to the Bellingham Mural Project lead by Sasch Stephens. The dial will be dedicated on the coming equinox, Sept. 22.

NASS members enjoyed this year's conference and are now planning for next year's convening, tentatively to be held in Denver, Colorado.

This year's Sawyer Dialing prize was awarded to Gianpiero Casalegno at the NASS annual conference in Pittsburgh, PA.  The certificate recognizes Gian for "his achievements in harnessing modern digital technology to the benefit of traditional dialists around the world - 18 Aug 2018."

Gian was not able to attend the conference to receive the Sawyer Award, so Fred Sawyer read the certificate to NASS attendees and forwarded the award certificate and a custom made Spectra Sundial by Jim Tallman of Artisan Industrials to Gian in Italy.  Gian chose to use the traditional cash prize of \$200 to support the Bellingham Mural Sundial.

Gian prepared an acceptance speech that was read by Sawyer.  Gian's began his talk with "My main contribution to gnomonics has been the development of several software programs [including Orologi Solari available to all at http://www.sundials.eu/download/download_enu.html]  to help other people dealing with sundial design, simulation and restoration. Therefore today I would like to present a survey of my programs highlighting some unique aspects that could have been neglected or underestimated by most people."

Fred Sawyer, in cooperation with the North American Sundial Society, established a continuing yearly award, the Sawyer Dialing Prize to be presented by NASS to an individual for accomplishments in or contributions to dialing or the dialing community. Each year a panel makes recommendations of those people who have significantly contributed to the art of dialing by their dialing art, their ability to teach and educate, their superb craftsmanship, their care in dial restoration, or in their gnomonic skills in design and computer programming tools for others.

At each North American Sundial Society conference since 2000, the winner is announced and awarded with a certificate of recognition, a small trophy sundial, and a cash award of \$200.  Many of the awardees have chosen to use their cash award to help further the art of dialing by donating it to others, increasing the scope of sundialing around the world.  Funding for this award has come from the Sawyer family with a 50% matching donation by NASS.

The certificate and trophy dial presented to each recipient are inscribed with the Greek letters ZHΘI.    The ancient Greeks used the letters of their alphabet as numerals.   When the hours of a dial were to be numbered from dawn to sunset, the numerals used were A, B, Γ, Δ, E, S, Z, H, Θ, I, IA, and IB for the successive hour intervals. By chance, the sequence from the seventh through the tenth hour (i.e. noon through mid-afternoon) spells a Greek word ZHΘI, the second person singular imperative meaning: Live!  The Greeks carried this thought further, and an epigram on the certificate, attributed to Lucian - a second century Greek satirist - exhorts:

The first three Sawyer Dialing prize recipients received a Universal Equatorial Dials designed and crafted by Tony Moss of Lindisfarne Sundials, UK. [Tony is now retired and the last of the Lindisfarne Sundials has been made.]  The dial can be set for any latitude and is a special edition containing the NASS logo and the imperative ZHΘI.

Since 2003, Sawyer Dialing prize recipients have received Spectra Sundials crafted by Jim Tallman.  Hundreds of Spectra Sundials can be located around the world at The World of Artisan Sundials - Spectra Sundial Locations Worldwide .  The unique design of each Sawyer Dial is given as an html link at the bottom of each award description.

This Sundials for Starters appeared in The Compendium in March 2007
(Updated January 2017)

By Robert L. Kellogg, Ph. D.

Benjamin Banneker, 1731-1806 , is one of the nation's best-known African American inventors.  He was born in Maryland and in 1791 played an important part in surveying the newly designed Federal Territory, now called the District of Columbia.  In his youth, Banneker was inspired to build his own clock after an acquaintance gave him a watch. He took the watch apart to find out how it worked and made drawings of each component, and based on his drawings, he carved larger versions of the components out of wood and constructed a clock that kept accurate time for more than 50 years.   As mathematician, he designed an Almanac that was a rival of Benjamin Franklin’s famous publication.

As astronomer, clockmaker, and mathematician, he was expected to know how to design sundials, although none exist bearing his mark.  In an age before pocket calculators, how would Banneker design a sundial?  The graphical method is available in modern texts such as Waugh’s 1973 classic “Sundials: Theory and Construction”.  Want to lay out a horizontal sundial without sines, cosines, and tangents?  Then this “Sundials for Starters” is for you.

 Bannaker- Dial Construction.pdf [ ] 2019 kB

Some years ago Bob Terwilliger built a Laser Trigon, an instrument that assists in drawing sundial lines on irregular shaped objects. For more about the Laster Trigon, see The Teacher's Corner - Sundial Projects. Here is the story of how he used it to create a bathtub sundial and after some years of service, how the sundial met its end.

The laser projects a beam of light to draw the lines and curves of a sundial onto any surface. To test the capabilities of his Laser Trigon, Bob decided to build a large combination vertical and horizontal sundial in his Florida home backyard … with some unusual consequences.  Here is his blog, taken from “A Dialist’s Notebook – The Shadow Garden

# August 31, 1996 – Planning the Garden Sundial

The Shadow Garden is an area in my back yard set aside for experiments in building sundials. The dials are transient, and all were made from found objects. Some are being built for fun - others to experiment with a method of construction.

Instead of putting a sundial in your garden, why not put a garden in your sundial? I am hoping the result [using the Laser Trigon] will be a fascinating and unpredictable garden of objects, some bearing hour lines, some numerals, some both, many neither. As the sun defines the day, its shadow will wend its way among them, anointing those it chooses with the power to tell time.

The first step is to make a working model. I need to get a feel for the relationship between the position of the gnomon and the west-facing board fence. The model consists of two planar dials, a horizontal dial joined to a direct west vertical dial. These surfaces will not be obvious in the finished dial, as the lines and curves will be located on the objects lying within the dial itself.

The Horizontal Dial is limited by the backyard space, such that only to the hours from10am-2pm will be seen, while the Vertical Dial to be attached to a north-south running fence will display the summer shadows to 8pm.

Next I installed the gnomon, which is made of fencing tubes and associated tee and elbow hardware. I temporarily located hour and half hour indicators on the ground by marking piles of whatever I could find.  The markers show the appropriate local solar time.

The hour line timing for this was done [with a now old] computer program, The Dialist's Companion, written by Fred Sawyer and myself for the North American Sundial Society. [Today a number of sundial calculators are available for your choosing, including:]

Orologi Solari by Gian Casalegno

zw2000 by Fer J. de Vries

Sonnenuhren by Helmut Sonderegger

Sundial Design by Miroslav Brož

A few of the objects I found to show local solar time (along with much pre-existing trash) are shown below the dial gnomon.

# October 23, 1996 – Rethinking the Size of the Dial

I have to rethink this dial. If you take a look at the full size photograph, I think you will agree that the scale of the objects I used are too small for the size of the gnomon and the overall garden area.  I am going to have to find larger objects, or settle for a design that uses less shadow receiving surface.

# February 21, 1997 - A Hot Tub is Found and Construction Begins

I may have solved my problem. I found a derelict fiberglass hot tub … a discarded Jacuzzi bathtub… which has a suitable variety of surfaces and angles. Instead of many small objects, why not one big one? Tipped up on an edge, it fits almost perfectly between the posts outlining my desired dial area.

The hot tub has been tilted up facing south. It sat naturally in this position, but I provided further support so that I can walk on it without the tub moving. Drainage is provided by drilling holes in the apparent low points of the tub.

In preparation for realizing my dial, I tested the Laser Trigon on the tub. Sadly, the original laser was not bright enough to properly illuminate the surface. I have now acquired a much brighter laser, which I’m installing in the Trigon. The problem of mounting the Trigon has, in principal at least, been solved.

[Lasers have come a long way since 1997. Today, a number of 3-5mW (Cat-III) lasers are available for moderate cost.  Brighter Cat-IV lasers are available for under \$1000]

# March 4, 1997 – Drawing the Lines

The new laser has been installed and it gives a perceptible dot. The mounting also works well, and I’ve already laid out the morning hour lines. I’ve scanned some Polaroid photographs to show the results.  The dial is being built for latitude 25° north, longitude 80° west.  My dial will include a longitude correction for the offset from the Eastern Time Zone at 75° west.

I’m using a sturdy tripod with a V rest on top and placed inside the tub as if to support the gnomon. Next, I’ll remove the gnomon and replaced it with the Trigon, which has been mounted on a length of the same tubing used to make the gnomon. The instrument and its tubing will be secured to the gnomon support post and rest on the tripod.  I’m including a photo of the Laser Trigon mounted on the tubing.

The instrument has replaced the gnomon and is positioned so the center of the axes of rotation is at the desired point of the nodus, a point that can be used to project the solstice limits of summer and winter and the mid year equinox line. The nodus point was somewhat arbitrarily chosen, but is close to the actual position of the nodus that will be determined more precisely by its shadow on the upcoming equinox. Another view of the process. Pepín tries his hand at the laser.

We start work at twilight, as the tub is too hot when in direct sunlight. This is our second session. Some of the lines have already been laid out and taped. I am directing the laser, Pepín is marking the position of the dot. The morning lines and three lines for declination are finished. The gnomon is back in place. The winter solstice and the equinox can be seen. The summer solstice is there, but it falls inside the tub. The lines are applied with 3M "Long Mask" masking tape. Hours and half-hours run through the tub. Quarter-hours are marked along the edges.

Interesting? It works for me.

# March 15, 1997 - A minor setback

During a windstorm yesterday, a heavy extension ladder blew down and fell on the gnomon that fortunately had been removed and placed on the ground for safety!  The gnomon was bent and will have to be replaced.

# April 3, 1997 – All the lines are finished

I have designed some numerals, which will be cut from vinyl by a signmaker who cuts custom letters with a plotter. The numerals will then be applied directly to the fiberglass. Gaps can be seen in the photo below for the numerals 1, 2, and 3. The time shown on the dial is just before 12:15 (the sharp eye will note - a bit after the equinox). The little numerals at the bottom are temporary.

Almost Finished

# April 17, 1997 – The Finished Dial

After six days without sun, I was finally able to photograph the finished dial.  View from the south. The time is just before 11:45.  The flags are those of the State of Florida and the United States of America.

This calls for A Party. Click the audio panel below and listen to the Beatles' Here Comes the Sun.

# March 20, 1998 - Performance of the Dial During its First Year

The hour lines were consistently accurate during the entire season. The taped lines themselves have faded slightly.

When making the Laser Trigon with my small clockmaker's machinery I encountered some problems laying out and machining the parts of the device necessary to produce the seasonal lines and curves. On the finished dial the winter solstice and equinox were reasonably accurate, the summer solstice less so. A bit of "tweaking" of the position of the nodus brought all the seasonal shadows within a half-inch or so of dead center. The results of the experimental dial were satisfactory, and some improvements to the seasonal adjustments of the Laser Trigon will produce an instrument which will, as advertised, "draw a sundial on a Buick".

# April 28, 2000 – The End of the Hot Tub Sundial

The dial was completed in April of 1997. After 3 years in the direct sun, the dial has decayed. The masking tape lines have faded and washed away. I made an attempt to put vinyl tape over them, but it would not stick. Weeds have grown up through the drainage holes. Since the dial is in Florida I have filled it with concrete cylinders to prevent it blowing away during a hurricane. (I have always been amused by considering what an interesting UFO the dial would make should it fly away, and what the people who found it might think of it.)  Fortunate for all, it has stayed put.

Dial Completed in April 1997                                             Dial in April 2000

Installation and removal of the concrete cylinders during previous hurricane seasons had thrown the dial slightly out of alignment. It had never been secured to a foundation and I have always considered it temporary. The dial has survived three years without experiencing a hurricane, and I felt the odds might be against it surviving another.  In April, 2000 we took the hot tub dial down.

Going                                                        Going

--- Gone ---

### Subcategories

• Article Count:
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• Article Count:
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• Fred Sawyer, in cooperation with the North American Sundial Society, established a continuing yearly award, the Sawyer Dialing Prize to be presented by NASS to an individual for accomplishments in or contributions to dialing and the dialing community.
Article Count:
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• In these pages is the famous tub sundial created by Robert Terwilliger using his laser trigon to lay out hour lines on a very irregular surface to create a working sundial.
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1
• Who are today's sundial artisans?  Here are several bioghraphies of several artisans that show the unique combination of talents in art, engineering, and mathematics.

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• This section is dedicated to Richard Schmoyer who invented the Sunquest sundial.  Please visit http://sunquestsundial.org/ as well.

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3