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
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 3D Print Challenge
With all of Richard Schmoyer's SUNQUEST dial drawings available on the web, I decided that it would be a fine 3D printing project for the North American Sundial Society. I use a filament 3D printer (Prusa i3 MK2) that heats plastic, allowing the filament to be extruded into any shape. The plastic I’ll use is Poly-lactic Acid or simply “PLA”, which is a biodegradable thermoplastic derived from renewable resources, such as corn starch in the United States and Canada. Elsewhere PLA comes from sugarcane or even tapioca root. To make the PLA flow properly the 3D printer must be heated to 210 Celsius.
So the challenge is to use the 3D printer to create parts that matched Schmoyer's detailed drawings suc as the equatorial crescent shown here at the right.
The Modeling Process
To render this drawing into a 3D sundial part, I use OpenSCAD, a public domain application for numerical computer aided design. The language is reminiscent of Visual Basic. But it focuses on creating and manipulating fundamental 3D basic shapes such as cubes, cylinders, and polygons under programmatic control. There is a set of translation and rotation operators for placement of the objects and Boolean operators for concatenating or subtracting one object from another.
To create the equatorial crescent ring I used two cylinders of slightly different size with vertically offset centers. A boolean operator takes the difference between the two cylinders, leaving the crescent. Other booleans drill out the slot, leaving a 3D stereolithographic file (STL) that conforms nicely to Schmoyer's drawing. The slot will allow the crescent to be rotated back and forth on the sundial’s meridian ring. This adjustment allows for both longitude correction of time and daylight savings time. As you’ll see in a moment, Schmoyer uses the gnomon itself to adjust for the equation of time.
The Slicing and Printing Process
Once I've designed SUNQUEST STL files, they need to be prepared for 3D printing. This step is called “slicing”. Here I use a program called Slic3r to take the STL object and decompose it into many horizontal layers, like pages of a book. These layers will be printed sequential by my 3D printer, ultimately forming layer by layer, the STL object in plastic. There are a number of slicing programs such as “CURA” , “Slic3r”, “CraftWare”, Netfabb, Rep-et-ier, and Simplify3D. After experimenting with a number of these programs, I prefer Slic3r. That’s “Slicer” with letter “e” turned backward in hacker format using the number 3. Here is an example of two of the many layers that make up the Equatorial crescent and a photo of it being printed.
The interior of the dial could be solid, but it is more efficient to select an infill pattern like a honeycomb that uses only 20 percent of the volume. Each layer is 150 microns thick. This is a compromise between fast printing that uses a 200 micro layer and wanting a very smooth, detailed surface using a layer as thin as 100 microns Assuming the same speed of extruder nozzle movement, the difference between layers made at 200 vs. 150 microns is the ratio 4/3 and saves 3D print time by one half hour. Even so, to print the Equatorial cresent, meridian quadrants and their braces takes about 5 hours of 3D print time. I've tried increasing the speed of the 3D printer but usually something happens that spoils the final object. So I have had to learn patience.
The most difficult part to make is the gnomon. For most equatorial and armillary sundials the gnomon is a simple rod casting a small shadow onto the equatorial time ring. But Richard Schmoyer took the shape of the sun's apparent seasonal motion in the sky (called the "analemma") and embedded it into the shape of the gnomon. As Schmoyer himself explained: "Time is shown, not by a shadow, or by one edge of the [gnomon] shadow as in the familiar garden sundial, but rather by a band of sunlight between two shadows cast by the gnomon onto the [equatorial crescent] time scale." “The gnomon is turned by hand on its axis to sharply define a band of sunlight illuminating the time on the equatorial hour ring. “
“But in reading the sundial, when either the winter to summer or summer to winter gnomon face is turned toward the sun and gradually brought to a position at right angles to the sun's rays, two things happen:
(1) "The effective slot width is reduced or pinched down, making a more narrow line of light fall across the time scale. Turning beyond a right-angle shuts out the direct sunlight entirely, but just short of a position squarely facing the sun, the band can be as fine as you care to see and use to interpolate between the [time mark] graduations."
(2) "The band of sunlight is shifted from the gnomon axis to fall earlier or later on the time scale by an interval necessary to show standard clock time instead of local sun time." This correction is known as the 'equation of time' and is made by the curve of the SUNQUEST gnomon."
Most important in this gnomon design is that it converts solar time back into civil time. The Schmoyer SUNQUEST dial allows you to read the time that corresponds to your wristwatch!
In November,1958 Richard Schmoyer created a detailed drawing of the gnomon showing the curve displacement for every week during the year. This was truly a monumental calculating and drafting effort. The analemma shape is accurately represented in the middle of the gnomon, but as one gets near the solstices, the analemma is physically stretched a bit to accommodate the rapid change in the equation of time. In his dial, Schmoyer allows “The effective portion of the enlarged curve [to be] brought into play by manually moving the entire gnomon axially north or south."
Rather than copy all of Schmoyer’s numbers to create the gnomon shape, I took the polynomial approximation to the equation of time (EOT) and used the sun’s declination to find the scaled gnomon displacement. This was probably the hardest part of designing the dial, since it forced me to make the gnomon of very, very thin rectangles… one for each 12-hour time span. These rectangular layers are like brickwork that are moved laterally to create a slight overhang and moved forward and back for the appropriate EOT displacement all according to the sun’s declination. Think of it as building a wavy wall one layer at a time, but each layer is perfectly straight.
Schmoyer Sunquest Sundial
by Robert L. Kellogg
My first encounter with the Schmoyer SUNQUEST Dial occurred many years ago in my youth. I had received an Edmund Scientific 4-inch reflecting telescope with a motorized clock drive for Christmas. By age 14 I wanted to take my telescope to the nearby San Gabriel mountains, so I was delighted by C.L. Strong's Amateur Scientist article in the October 1959 issue of Scientific American describing a transistorized drive for a telescope. But in that October 1959 Amateur Scientist there was also a discussion of a sundial that keeps accurate civil time. I didn’t understand the peculiar gnomon or the shape of the analemma, but somehow this sundial captured my attention. As I read that article,
In that Amateur Scientist article C.L. Strong quotes a letter from Richard Schmoyer that still holds true today:
"...you raise the question of why a man who owns a accurate watch and several clocks will go to the trouble of building a sundial. Few will disagree with your conclusion that he is motivated in part by the intellectual charm of a device which, without moving parts, can convert the sun's changing position directly into time. But sundial-making holds other attractions for its enthusiasts. In the course of developing a sundial one is exposed to a fascinating and well-defined mixture of mathematics, geometry, geography and astronomy. The design of a sundial challenges our creative talents, and its construction puts our craftsmanship to an exacting test. Finally, the designer who permits the primary time-telling function of the sundial to control its form adds spice to the project. Hardware in pleasing though strange and unexpected shapes often emerges from the equations which describe the ever-changing slant of the sun's rays."
"These inducements led me to design a sundial last year which has become a continuing source of pleasure both to me and to my neighbors. With only a few simple settings during two seasons of the year the sundial can be made to indicate accurate clock time... Most people find sundials attractive, so one must not altogether dismiss their ornamental properties. The structure of my dial was derived from the armillary [sundial]... The transformation from armillary to nested crescents demonstrates how a pleasing shape can emerge from a functional necessity. A good time-telling device should always fulfill its mission."
There are a number of Schmoyer Sunquest dials in botanical gardens, science museums, and on observatory front lawns. The Sunquest Sundial website describes the man behind the sundial as, "He was a charter member of the North American Sundial Society (member #53) and a member of the British Sundial Society, and was always eager to help aspiring sundialists with their work." The Schmoyer SUNQUEST dial is basically an equatorial sundial of elegant proportions.
Richard Schmoyer, Jr. and Amy Roe, his grand daughter, have created a website in his honor at http://sunquestsundial.org/ . His dials and drawings are posted there for sundial enthusiasts everywhere.
NASS will hold this year's annual conference Thrs 16 Aug - Sun 19 Aug in Pittsburgh, Pennsylvania. The conference will be held near the famed University of Pittsburgh campus with its Cathedral of Learning. The conference will be held at the Hilton Garden Inn, Pittsburgh University Place 3454 Forbes Avenue in Pittsburgh.
NASS has a discount rate for the conference at $119/night (plus tax). This rate will also apply 4 days before and 4 days after the conference, if rooms are available. You can call the Hotel at 412-683-2040 for reservations or visit the Hilton webpage specifically set up for NASS reservations at: https://bit.ly/2ERRW0I The hotel is about 20 miles from Pittsburgh International Airport with SuperShuttle transportation to the hotel at https://www.supershuttle.com/locations/pittsburghpit/ Use the GUENB to receive a discount round-trip ticket.
NASS has two registration types: Full and Partial. The Partial Option is only for Thursday Evening Reception, Saturday Conference Dinner, and the Friday Tour of Pittsburgh Sundials. The Partial Option does not include admission to the general sessions. Use the attached form (see below).
|Conference Registration||Until June 15||June 16 - July 15|
|w/Filet Mignon Dinner||$302||$192||$327||$217|
|w/Chicken Marsala Dinner||$290||$180||$315||$205|
|w/Fire Roasted Tortellini Dinner||$285||$175||$310||$200|
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/
Richard Mallet at Cornell Univ. Sundial
Richard Mallet, former British Sundial Society Trustee, Council Member and former BSS Webmaster passed away on Nov 7th, 2016 with funeral held on Dec 12th, 2016. He lived in Eaton Bray, UK and had many interest in physics, mathematics, and sundialing. Those of us maintaining websites know of the difficulty in perserving order, yet always allowing for expansion of new material. "After a near disaster with the [British] Sundial Society's then heavily modified and entirely non-compliant website, Richard stepped in at no charge to the Society to rewrite it using the then new Expression Web software from Microsoft. This proved very successful and was of course fully W3C compliant."
Over the next year, the North American Sundial Society website will migrate from an older version of the Joomla Content Management System to the fully maintainable Joomla 3.x version. The majority of content and organization will remain intact, but new innovations are expected.
Read more about Richard Mallet's life at: http://www.ppowers.com/mallett.htm
Portland Maine WCSH Channel 6 presents local and national news and the usual sports, weather and traffic. But on a recent 207 broadcast, they reported an invasion ... an invasion of sundialists coming to Portland, Maine for their annual conference and their search for a dial made over a century ago by Albert Crehore that might still be somewhere in Portland.
Members of the North American Sundial Society (NASS) take the art and science of sundials very seriously. Watch the video and consider joining NASS for even more sundial adventures. Visit Portland Channel 6 News:
Sundials for Starters
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Sawyer Dialing Prize
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.
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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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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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