Seattle, WA wants to call itself the sundial capital of the world, but it runs a pale second to Birkenau, Germany. This small village in the south of Germany with about 10,000 inhabitants holds the record as the village with the highest density of sundials in the world. (https://www.sonnenuhren-birkenau.de/service-269/news/news-details/world-record-for-the-village-of-sundials.html). You can find sundials everywhere: on homes, in gardens, on the walls of public buildings, and there is even a Sundial Park with 28 dials by Vinzenz Philippi a sundialist from the Saarland region and 5 other dials from other dialists.
The Birkenau Sundial Society offers tours of the village sundials in German or English. If you venture out on your own there are four sundial trails with each dial clearly labeled.The majority of the dials are vertical and easily visible from the street. The second most polular dial is the Equatorial.
For only 2€ you can get the Birkenau sundial cube, a decorated cardboard box with a horizontal sundial on top. https://www.sonnenuhren-birkenau.de/service/kontakt.html The dial's gnomon is a pencil set for Birenau's latitude and longitude (40.5 deg N, 8.7 deg W).
The Birkenau Sundial Society promotes and preserves the historical sundials in Birkenau, constructs new sundials and documents all of them. https://www.sonnenuhren-birkenau.de/sundials-in-birkenau.html
The North American Sundial Society, after by-passing the 2020 Conference due to Covid restrictions, held the 26th annual meeting from August 5th - 8th at the Hilton Garden Inn, Center City, Philadelphia. The venue was similar to past conferences: Thursday night social and door prizes for attendees, Friday a bus tour of 11 sundials in the Philadelphia area, Saturday sundial presentations and annual dinner, finishing on Sunday with more sundial presentations and the annual general meeting (AGM).The dial tour took us walking through Philadelphia parks and arboratums and visits to University of Pennsylvania, Swarthmore College, and Haverford College.
At Swarthmore we saw the modern vertical declining dial on Kohlberg Hall, designed by Martin Cowan. Frederick Orthlieb, professor and chair of the Dept of Engineering at Swarthmore "had a part in locating the bent-plate gnomon so as to give correct indications on the vertical wall. As installed, the gnomon's indicating edge (which lies on a Polar Axis) casts quite a short shadow in Autumn and Winter and requires some observing skill to make a close estimate of indicated time, but in Spring and Summer the longer shadow moves over the granite hour marks very plainly."
For the annual group photo attendees gathered around the "Point Where Things Change", a N-S meridian dial commissioned in 2001 by the Redevelopment Authority of the City of Philadelphia and designed by Michael Grothusen. The dial is on the grounds of Tasepoint Corporate Headquarters.
From Left to Right: Bill Gottesman, Joyce Robinson, Pam Morris, David Robinson, Bob Kellogg, George Wilson, Jack Aubert, Will Grant, Betsy Wilson, Jim Holland, Bill Thibault, Art Paque, Tish Grant, Fred Sawyer, Philomena Sawyer, Phyllis Montgomery, Jeff Kretsch , Mark Montgomery, Marvin Taylor, Zoon Nguyen, Kate Aubert, Pat O'Hearn, Roger Dignard, Paul Ulbrich.
By the Light of the Moon
Photo by Dr. Jeff Kretsch
The analemmatic (human) sundial at Turner Farm Observatory Park in Great Falls, VA made by Eagle Scout candidate Kenny Dieffenderfer and Troop 1547 marked a unique place in sundialing history this July 23rd. The Analemma Society sponsors free Friday night public viewing of the heavens through telescopes at Turner Farm's Roll-Top Observatory. But just outside the Observatory on the sidewalk is Kenny's analemmatic dial. Could this dial tell correct time by the light of the moon?
On July 23rd this question was put to the test. It was almost exactly a full moon and the sky was clear. As can be seen in the accompanying photo taken by Dr. Jeff Kretsch at approximately 10:10pm EDT, the lunar shadow of a volunteer human gnomon cast a shadow of about 9:10pm standard moon civil time. How did this come about?
The important facts needed to make the analemmatic dial tell the correct "moon time" is knowing both the phase of the moon and the declination of the moon. On that night the moon was very close to being exactly a full moon and the declination of the moon was 25 degrees south of the equator. The maximum that the sun ever gets is 23.45 degrees south of the equator at the winter solstice. That means that (with practical precision) even though it was a late July night, the human gnomon must stand on the dial's zodiac walkway at the Dec-Jan winter solstice mark.
If this were the sun, we apply a plus 8 minute correction for the 77 deg west longitude of the observatory. The moon gets the same treatment. But what about the moon's phase and the "equation of time"? Here we find a fortunate coincidence: The moon was full moon at 10:37pm EDT on that Friday night, so by luck the moon was almost exactly opposite the sun. The moon's average full moon to full moon (a synodic month) is 29.53 days. Thus the average moon's lead or lag of a mythical full moon is about 49 minutes per day. Therefore the lunar phase correction is approximately 49 x 20/1440 = 0.68 minutes (41 seconds) ahead of the average full moon. Finally the sun's EOT for Friday July 23rd is approximately 6min 30 sec to be added to a dial's shadow to get civil time. But the moon opposite the sun has EOT in the opposite direction of minus 6min 30 sec. The net lunar correction is therefore +8.0 -.68 -6.5 = 50 sec, just less than one minute that needs to be added to that night's observation analemmatic shadow. One might say that the moon and sun were in perfect alignment!
Dr. Jessica Warren, lecturer of physics and astronomy at Indiana University Northwest, is active in science outreach and education. She is also passionate about sundials. For Indiana University outreach shecreated a video "The Garden Sundial - Much More than an Ornament" that presents a brief history of the sundial, how they work, and where to get one or make one.
You can watch the video on YouTube at https://www.youtube.com/watch?v=K10nPV69Q1A. It is also part of the North American Sundial Society library of videos, found on this website at https://sundials.org/videos/making-and-using-sundials.html where NASS has a collection of videos on sundials, timekeeping, and interviews with sundialists on how they make sundials.
At the end of her presentation, Dr. Warren provides a list of reference material about sundials. Her entire video including references is available as a PDF and is available for download at the bottom of this article. Additional references and sundial topics are available on the NASS sundial links page: https://sundials.org/dial-links/general-sundial-links.html. Read more about the fascinating world of sundials.
The first sundial in the NASS Registry is the dial from Carefree, Arizona. This 35 foot tall dial was designed by architect Joe Wong and solar engineer John Yellott and when built in 1959 was considered the second largest sundial in the world. You can see in the accompanying photo that hanging midway along the sundial's gnomon is a garish colored ball, a "Sunburst". [It is partially hidden by a background palm tree.] This structure was part of the original design. From the on-line Carefree City SunTimes, editor-in-chief Kathryn Miller brings us the story of its origin, demise, and now its restoration. The seven-foot wide wrought iron Sunburst has not been on the gnomon for the last 20 years. From Miller's article, "As the story was told by Carefree Vice Mayor John Crane in his March CITYSunTimes column, “The Joe Wong designed Sunburst enjoyed a short life. In 2004, when the Sunburst was determined to be beyond repair it was donated to the Cave Creek Museum where it resided outside for many years."
Eventually the museum returned the rusting icon to the City of Carefree, ending up in the Town garage. Miller's article now reports it's restoration that was completed in March 2021: "...[Back in] 2019, a Carefree resident, who prefers to remain anonymous, took it upon himself to return this misplaced, but not forgotten, historic and iconic art piece to its rightful place. Now, a reincarnated Sunburst, dimensionally identical to the original, but with improved design and modern materials, holds a place of honor in the Town center, once again celebrating the desert sunshine and casting its glow beneath the Sundial."
Perhaps an indicator of the times with the urge to turn night into day, this Sunburst that hangs on the gnomon is now electrified and illuminate with LED lights, blending in with the LED lighting of surrounding cactus in ithe plaza.
Want to travel? Want to see sundials? Well, you can do both by taking a virtual tour of the Galileo Museum (Museo Galileo) in Florence, Italy. Beside showing you detailed sundials, astrolabes, and quadrants in their collection, they host a series of short 2 minute videos on sundials and many other topics.
This is a fun virtual site to explore: https://catalogue.museogalileo.it/ Here you can read about the biography of Galileo or many other famous scientists or you may want to browse many of 1000 astronomical instruments in their collection, or watch a video on Galileo's astronomy or see how the the heavens can be seen in the armillary sphere sundial, or consider the history of the lightning rod with a demostration of gunpowder blowing apart a small wooden house (called a "Thunder House") that doesn't have one.
There are many short videos about sundials and astrolabes. And of course there is the Monumental Sundial at the entrance to Museo Galileo. Click here to watch a short animation of how this gnomonic sundial works. The Museum has many of these instructional videos. Be sure to visit their video catalogue: https://catalogue.museogalileo.it/index/VideoIndexByThematicArea.html
This article is reproduced by permission from Hudson Valley on-line magazine of Feb 17,2021 and can accessed directly at https://hvmag.com/life-style/history/missing-sundial-hudson-valley-hillside-dean-sage/ It was written by Jonathan Ortiz with information from NASS/BSS member Martin Jenkins and fellow researcher Kevin Franklin.
Menands’ village historian dives headfirst into the past to discover the whereabouts of a sundial that once resided at the Hillside estate in Albany County. There’s a mystery to solve in the Hudson Valley. It involves a cast of unlikely players: a local historian, a British society, a wealthy Albany County businessman, and a famed Scottish novelist.
Sun-Dials and Roses of Yesterday / Wikimedia Commons
The object of their attention? A missing sundial. Its last known whereabouts are the estate of Dean Sage, in Albany County’s village of Menands, which lies inside the Town of Colonie; however, this conundrum begins much, much farther away — in Scotland, to be exact.
“It’s a trans-Atlantic mystery,” says Kevin Franklin, Menands’ village historian and a former Menands police officer.
In 2020, Franklin was contacted by Martin and Janet Jenkins, two members of the British Sundial Society. They sought information about Hillside, the former Albany County estate of Dean Sage, son of Henry W. Sage of famed lumber firm H.W. Sage Co. fame. Hillside is located on the north side of the Menand Road (now State Rt. 378).
Interestingly enough, their purpose in finding this sundial makes the story ever more complicated. The device once located in Menands is actually a replica of another sundial from the Abbottsford estate of famed Scottish writer Sir Walter Scott. Now, there stands only a pedestal upon which the original sundial once sat.
“It is not known what the Scott sundial looked like,” writes Martin Jenkins in a letter to Franklin. “If the replica sundial made for Hillside could be traced, then a replacement replica could be made for Abbotsford in Scotland, the pillar then no longer standing silent and unadorned.”
Several books make reference to both the original sundial and the replica. Most recently the March 2019 edition of the British Sundial Society Bulletin by Denis Cowan refers to the fact that a replica sundial was made for “Hillside, Menands, NY.” The 1902 edition of Sun-Dials and Roses of Yesterday by Alice Morse Earle shows the replica sundial to be in existence at Hillside, in the Shakespeare Garden border. In Ye Sundial Booke by T. Geoffrey W. Henslow in 1914, there are two sketches, one showing the sundial pillar at Abbotsford, Scotland, and the other depicting the replica sundial at Hillside.
Lastly, in The Book of Sun-Dials, the author Margaret Gatty apparently made her sketch of the sundial pillar at Abbotsford in 1839, but, by then, the sundial was missing — more than likely stolen.
Despite extensive documentation, many questions remain. What was the connection between Sir Walter Scott and Hillside? Who commissioned the Hillside replica? And, most importantly, what happened to the replica?
It was here that Franklin picked up the trail, starting with the local angle: Dean Sage.
“The Sages were immensely wealthy,” explains Franklin. “Their wealth evolved around the exporting of lumber from the Michigan area across the Erie Canal to the ‘Lumber District’ of Albany.”
Researching Sage’s background did reveal one important fact, and the potential connection between him and Scott: Sage was both a bibliophile and an avid fisherman.
Replica of Sir Walter’s Sundial | Photo by Alice Morse Earle, public domain
He wrote the famous fly fishing book Ristigouche and Its Salmon Fishing in 1888. It was published by David Douglas of Edinburgh, whose name also appears in Sun-Dials and Roses of Yesterday. There, it is stated that Sage’s replica sundial was, “commissioned by the publisher Douglas.”
Douglas has another publisher’s credit — in The Journal of Sir Walter Scott. Scott kept a daily journal from 1827 until his death in 1832. These journals were published in 1890 by the very same Douglas who published for Sage.
While Sage, born in 1841, could never have met Scott, who died in 1832, it is well known that Abbotsford is on the banks of the River Tweed and has been famous for salmon fishing since Roman times. The Tweed Commissioners whose responsibility it was to manage the river and its fish was set up by Scott in 1805. It seems likely that Dean Sage visited Abbotsford at some time as part of his salmon fishing interest.
“It would not be beyond the realm of imagination for Dean Sage to have gotten either a sketch or drawing, maybe even a photograph, of this sundial at least the base that still remains at the Abbottsford and had that duplicated,” explains Franklin.
The final question remains: Where is the Hillside sundial?
Mr. Franklin continues to follow up with past residents of the area and any leads which would help locate the missing sundial of Hillside.
Everyone is excited about the landing of Perseverance, the Mars rover. If you look closely at the first panorama of the Martian landscape you will see on the equipment bay of Perseverance the Mastcam color calibration target. It sort of looks like it could be a sundial. In 2004 a similar calibration target was used as the first Martian sundial, designed by Dr. Woody Sullivan and Jim Bell with the support of The Planetary Society and Bill Nye, "The Science Guy" [See PDF at bottom]. Is the Mastcam color calibration target a sundial as well? Here is Dr. Sullivan's answer to a group of sundial enthusiasts (2/25/2021):
"The short answer is “No”. The longer answer follows. The new object on Perseverance (officially the "photometry calibration target") has obvious similarities to the Mars dials on Spirit and Opportunity that landed in 2004, and in fact it is a technological and aesthetic “grand-daughter” 17 years later. (The intervening generation is the Curiosity rover, which landed in 2013 and is still alive). The Mars dials that a small group of us designed and fabricated and then occasionally “used” to read Martian time were a great experience for me.
"But after over a decade of Spirit and Opportunity, I decided not to get involved in any future NASA missions — they gobble up a lot of time! The science and fabrication of the new calibration target (as for Curiosity) is led by a group at U. of Copenhagen.
"Nobody has ever done anything with the orientation of the shadows cast by the “gnomon” on Curiosity and I’m sure nobody will for Perseverance either. By the way, independent of gnomonics, the vertical tube has a vital scientific purpose: its shadow on the gray and colored patches allows one to calibrate camera images properly in shadow as well as sunlight.
"The various symbolism and messages on Perseverance also stem directly as heritage from Spirit and Opportunity . You can find a tremendous amount of detail about all aspects of the Perseverance cal target (including construction) at https://mastcamz.asu.edu/mars-in-full-color/ [See PDF at bottom]. The feature I like best is the motto “Two Worlds, One Beginning”, which nicely refers to Spirit and Opportunity ’s “Two Worlds, One Sun” as well as early solar system history and the possibility of early life on Mars. (Curiosity has the terrible motto “To Mars to Explore”.)
"Nevertheless, I watch the procession of missions with great astrobiology interest. And someday I will write up the whole Mars dial experience, including many Martian landscape images in which it appears, and how a student and I were actually able, using its shadow, to measure the Martian analemma at local mean (“clock”) noon over a Martian year ( = 1.9 Earth years).
— Woody Sullivan
Prof. (Emeritus) Woodruff T. Sullivan, III
Dept. of Astronomy & Astrobiology Program Box 351580
University of Washington
Seattle, WA 98195 USA