Sundials - World's Oldest Clocks

North American Sundial Society

nass news 2021 feb Mastcam Z on PerseveranceEveryone 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 [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

NASS_2004_TwoWorldsOneSunAt the 2004 NASS Conference in Tenafly, NJ, Fred Sawyer announced that the Sawyer Dialing Prize would go jointly to Bill Nye and Woodruff (Woody) Sullivan for their efforts to transform the Mars Rover Pancam calibration disk into a Martian sundial (with electronically placed hour lines) that could be viewed on the Internet.  The award was a foregone conclusion at the inception of the prize some years ago, but awaited the success of the Mars Rover landings in 2004. [Photo Credit: NASA/JPL/Cornell]

Unfortunately neither Bill nor Woody was able to attend the conference, but a descriptive paper by Bill was read explaining the corresponding Earth Dial project (“Two Worlds, One Sun”), showing similar styled dials in Utah, Honduras, Ohio, Virginia, Chile, Canada, the UK, Spain, and even the South Pole.  Download the PDF created by Nye Labs at revealing how to make a replica of the Mars Dial.

Read more: 2004 Prize - Bill Nye and Woodruff Sullivan

nass_news_2013_mar_EarthDialThe Planetary Society and Bill Nye, The Science Guy, are bringing back the Earth Dial, which is a simple to make gnomonic horizontal sundial reminiscent of the sundial incorporated into the Mars rovers Spirit, Opportunity and now Curiosity.  Their original and fundamental purpose is to serve as test patterns for the rover cameras, but they also provide an opportunity as unique shadow casting sundials.

“Since we had shadows being cast on Mars, I suggested it be a sundial… I admit I was quite enthusiastic about it. Steve Squyres, the Principle Investigator on the Spirit and Opportunity missions, made the call, and the Mars Dials were created. He received the [Planetary] Society’s Cosmos medal a few years ago, for his wonderful leadership of the project.”

Download this file (EarthDials-2013.pdf)EarthDials-2013.pdf[ ]923 kB

Read more: Planetary Society Brings Back Earth Dial

nass_news_2012_oct_SundialToMarsBill Nye, The Science Guy gives a 7 minute TED-ED talk describing the excitement of creating sundials on Mars.

TED stands for Technology, Entertainment, and Design, a nonprofit organization devoted to spreading ideas of worth.  Conferences are held each year with more than 50 guest speakers to motivate the audience on many different fields and now through YouTube, you can share the excitement of sundialing.

Download this file (MakeYourMarsDial_NyeLabs.pdf)MakeYourMarsDial_NyeLabs.pdf[ ]976 kB

Read more: TED Lecture - Sundials to Mars

nass_news_2012_aug_CuriosityWith the successful landing of the NASA rover Curiosity, another sundial is on planet Mars.  Turning the color calibration target into a sundial was the idea of Bill Nye, the Science Guy, and Professor Woodruff Sullivan at the University of Washington, originally hailed by “Two Worlds – One Sun”

Read more: Curiosity Carries Sundial

[photo courtesy of NASA]

“Two Worlds One Sun” lives on as the Mars Science Lander called Curiosity makes its way to Mars, once again carrying a camera color calibration target that will be used as a sundial.  The original Mars sundial was the idea of Bill Nye, the Science Guy, and designed by Professor Woody Sullivan of University of Washington.

The spacecraft was launched toward Mars on 26 Nov 2011.  Onboard Curiosity the camera calibration sundial has four edges each containing a panel of text and image, written by Jim Bell, planetary scientist from Arizona State University and the Mars Exploration Rover team with graphics designed by artist Jon Lomberg. 

Read more: Curiosity Sundial Launched

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