More than 25 years ago Robert diCurcio made a compound sundial. A small round horizontal dial is surrounded by a larger gnomonic dial engraved with hour lines in the shape of analemmas. Careful inspection of the dial shows that the lines are offset from the longitude of 70 degrees to account for the sun at the eastern time meridian of 75 degrees west. In "Yesterday's Island - Today's Nantucket" Katherine Brooks of the Maria Mitchell Association (MMA) takes a close look at the sundial in their front yard, sitting on the lawn of the Maria Mitchell Observatory on Vestal Street.
Here is a slight correction to the article's text: diCurcio set up the sundial perfectly level and oriented it so that the meridian-line is exactly north-south. [Hopefully aligned to true north, NOT magnetic north.] Once the dial is aligned the triangular gnomon will cast a shadow not only for the small horizontal dial telling east coast solar time, but the tip of the gnomon shadow points to the analemma, the “figure of eights”, which shows standard or daylight mean time (clock time). Installed by diCurcio, the sundial at the Maria Mitchell Association is accurate to this day. Brooks writes,"We hope you stop by the Maria Mitchell Vestal Street Observatory on Vestal Street to see the 1908 observatory built by the MMA and to test out the Sun d’Isle on the lawn in front. If reading shadows interests you, we encourage you to attend our Summer Speaker Series this Tuesday, August 30, to learn about the “Effects of Light at Night” with Dr. Mario E. Motta."
Compare the photo of the MMA sundial from Brook's article http://yesterdaysisland.com/what-is-this-a-sundial/ with the sundial photo above that appears in the NASS Sundial Registry at http://www.sundials.org/index.php/component/sundials/oneDial/513
In the old Roman Agora on the slope of Athen's ancient Acropolis hill is the Tower ofWinds. Today, completing two years of restoration, the interior was re-opened to the public this summer in August, 2016. The Tower had been closed for the last 200 years. The story of the Tower starts in the first century, BCE, probably during the reign of Julius Caesar.
The Tower was designed by Andronikos Kyrrhestos (Andronicus of Cyrrhus), an astronomer and maker of celestial instruments. Andronicus constructed a white marble sundial for the sanctuary of Poseidon and Amphitrite on the island of Tinos. The sundial becamse so famous that Andronicus was invited to Athens where he erected the magnificent 14 meter Tower called the Aerides (the Winds) . It was built on the eastern side of the Roman Agora in Athens and meant to have utilitarian value. "No one knows who funded its lavish construction - the octagonal monument is made almost entirely of Pentelic marble, the same used for the Parthenon and rarely found in buildings other than temples," said Stelios Daskalakis, head conservator.
Atop of the octogon tower now rests the fully-preserved roof made of 24 marble slabs, resting on a Corinthian capital. Once a bronze statue of Trition, the god of the sea, was set on the roof to turn in the wind as a weather indicator. By night, water flowed through a hydro-mechanical system designed by Andronicus from a cylinder inside the Tower. The water level lead to an exterior indicator creating a night time clock or clepsydra. During the day the Tower was a public time teller with eight sundials.
Michael Lee's photograph of Central Park started it all. Erika Owen (TravelandLeisure.com) wrote "If you think Central Park is only good for its slightly quieter reprieve from the hustle and bustle of the Big Apple, you're missing out. As it turns out, the park can actually be used as a giant sundial. Understandably, this isn't a universally accessible perk of the park...you'd need to be in an airplane or helicopter to truly appreciate the functionality."
Any vertical ediface such as a tall building, a flagpole, or even the Washington Monument can become a gnomonic sundial measuring time by the tip of their shadow. But seeing those shadows on the ground results in fuzzyness of the penumbral shadow. The solution? Step back, way back to a perspective of seeing the shadows from high in the air. From this view these giant sundials become visible. Owen continues, "Billionaire's Row, the name given to the skyscrapers lining the two blocks south of the park between Fifth Avenue and Central Park West gives off plenty of shadows..."
To see the shadows in motion, Cube Cities presents a short video "Central Park Shadows". Cube Cities specializes in urban city representations and animation software to create them. For example they visualize the growth of cities as Manhattan from the 1920s and the growth of San Franciso from 1977 to 2015 and Chicago from 1862 to 2014.
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:
An analemmatic sundial was dedicated July 4th 2016 at noon in the Frontier Heritage Park at La Pine, Oregon. The Daniel and Crystal Richer Family Foundation created a simple but accurate sundial where one's own shadow tells the time. The sundial honors veterans and the unmentioned heros of our country. The plaque sums it all: "Always Remember".
The video is from KTVZ, Channel 21: http://www.ktvz.com/news/new-la-pine-sundial-to-honor-veterans/40269620
News Item from the Wet Mountain Tribune on June 30th, 2016: Custer County courthouse is getting a new sundial. Using a true north line surveyed by county commissioner Kit Shy, Charlie French is cementing a rod anchored in obsidian rock, whose shadow will align with that of the courhouse flagpole. "Taking advantage of the summer solstice on June 20, he literally nailed down the farthest reach of the flagpole shadow."
While French happily proclaims, “thanks to Harrison [whose clock allowed longitude determination in 1761], and knowing where the time zone meridian is, and how distant we are from it, we are accurate to one minute and 51 seconds of Mountain Time here in the visible solar time at the courthouse.” Well, that's almost correct. French's gnomon rod and courthouse flagpole shadows align at local solar time. Mountain Time like other clock times do not match solar time due to the tilt of the earth's axis and eccentric orbit around the sun, shifting solar and clock time by +/- 15 minutes throughout the year. Read more at: http://www.wetmountaintribune.com/home.asp?i=945&p=6
Did you know that Thomas Jefferson designed sundials and thought that a book of trigonometric tables was one of his most valuable books? And that Benjamin Franklin made a "modest" proposal for an extension of the noon-day sundial canon? Join Fred Sawyer, eminent sundialist and president of the North American Sundial Society as he explores sundial history with the United States founding fathers George Washington, Benjamin Franklin and Thomas Jefferson in three video presentations. The videos are taken from a presentation he made two years ago at the annual meeting of the NASS in Indianapolis. See these videos at: http://www.sundials.org/index.php/dial-links/videos/historic-sundials
Learn more about sundials, their construction and their history by joining the North American Sundial Society. Go to http://www.sundials.org/index.php/join-nass/join-nass and join now.