USF Curiosities: A solar rotary?

June 20, 2024 By Lesley Brooks
Share:
Page Link Copied!
Reading Time: 5 minutes

Summer days are here at last! Today, we will experience not only the first day of summer but also the longest day of the year.  

In the Northern Hemisphere, the June solstice (aka summer solstice) occurs when the Sun travels along its northernmost path in the sky. This marks the astronomical start of summer in the northern half of the globe. 

The Old Farmer’s Almanac 

 

And where should you go to celebrate the first day of summer? To the Solar Rotary, of course! 

Solar Rotary by Nancy Holt (1995). Solar Rotary at Summer Solstice as seen from the Communication and Information Sciences building. http://www.ira.usf.edu/PA/Pages/pa_holt.html

 

Want to learn more about this fascinating moment in USF history?

Solar Rotary is a public art project by Nancy Holt, built in 1995. Located on the Tampa campus near the Tampa Library and the Muma College of Business, it “functions as a henge … like Stonehenge, it utilizes the movement of the Sun, vis a vie a particular spot on Earth, to mark certain events.”[1] 

The project description further explains that: 

At solar noon on the day of summer solstice, Solar Rotary‘s shadow caster casts a circle of light around the central seat. On five specific days of the year, at times specific for each day, Solar Rotary casts its circle of light around plaques placed in the ground plane of the plaza that mark historic events for the State of Florida and the city of Tampa. Additional seating is provided both around the perimeter of the plaza, and on four benches set into the nearby landscape marking the cardinal directions, North, South, East and West. [2]

In the 50th Anniversary Oral History Project, Vincent Ahern, former Director of Public Art at the USF Institute for Research in Art, explains how the Solar Rotary project came to be. 

It’s a project by Nancy Holt, who was one of those artists who we, in the stealth years, identified and decided we would go after this very ambitious project. I think we had at the time 43,000 dollars to do the project. Eventually the project would cost a little over $100,000. So, Nancy agreed to take it on, designed Solar Rotary as we know it today, and then told us what it would take to actually get it built. And we realized [s]he had a significant funding need. It coincided, the design of Solar Rotary, with the 100th anniversary of the Tampa Tribune. And so working with folks from development, we made an approach to the Tribune and they agreed to give us 57,000 dollars. In return we—and it’s really the first time we did it. We realized that’s more than 50% of the budget, let’s give them a naming opportunity. So, Solar Rotary, there’s a plaque there that credits the artist and provides the title. But there’s a second plaque there that identifies the site as the Tampa Tribune plaza. So, we had the funds to build it. The piece itself is an amazing piece. It functions as a henge. Meaning that, like Stonehenge, it utilizes the movement of the Sun, vis a vie a particular spot on Earth, to mark certain events. 

There are five historic dates associated with the State of Florida that are marked in plaques, 12 inch bronzed plaques in the ground plain. And these plaques each mentioned the historic date. The date, for instance, that Ponce de Leon sighted Florida. I believe it’s March 27th. Each year on March 27th, at a time specific, 12:17 PM, the plaque is perfectly surrounded by a shadow cast from the structure itself. There is a, in the center of the Solar Rotary, 20 feet above ground plain, there is a circular form created by using the materials that the piece was built out of, a 5 5/16 inch diameter pipe that’s held aloft and causes a circular shadow to be cast on the ground plank. Well, that circular shadow perfectly centers the plot in such a fashion that the shadows cast from the horizontal poles are precisely equidistant on either side of the circular shadow. All of this was critical to the artists and critical to the project. I mentioned professor emeritus Jack Robinson and his role in wanting to calculate where a shadow will fall at a specific time on a specific date at a specific site. That was three years of research and development that was required. We worked with Jack to do the calculations, we worked with graduate students from engineering to do measurements down to a tolerance of 1/128th of an inch for any placement of any part of that sculpture so that the piece would in fact function in the atomic moment that it was predicted to function in. Then the piece had to be built to exact intolerances. No dimension of the piece could be off by anything more than a quarter of an inch in any direction; vertical, horizontal, distance from the ground plan, etc. or the piece simply wouldn’t function. In fact, works, and we’ve checked this to the atomic moment, and so, on these occasions, let’s just say five plaques, and local apparent noon on the day of the summer solstice, these solar events occur where in alignment, a very precise alignment is visible to the viewer, provided it’s a sunny day. If you recall this year, a week ago Saturday, was summer solstice and we were having an awful lot of rain. However, the sun’s movement through the sky slows down just a bit around solstice. And so you can see it a few days before, a few days after. Now it’s not exact. It’s off a little bit to the north or a little bit to the south but it’s pretty darn close, too. So, we had the opportunity, my assistant and I, to go visit the sight this last Monday at local apparent noon. Which here, by the way occurs between 1:31 and 1:32 PM. That’s a calculation of where we are on longitudinally, and of course, the fact that we’re in daylight savings time. So, clocks move ahead an hour. We’re on the western edge of the Eastern Time Zone. So, apparent noon, local apparent noon occurs between 1:31 and 1:32 PM for the day of summer solstice. We went there the other day at that time and, sure enough, our shadow was there to kind of celebrate the solstice. 

USF 50th (2006) Anniversary Oral History Project, “Vincent Ahern,” (U23-00002) p. 16-17, https://digital.lib.usf.edu/SFS0024312/00001 

 

To see images of and additional information on Nancy Holt’s Solar Rotary (1995), please visit the USF Institute for Research in Art Public Art Program site: http://www.ira.usf.edu/PA/Pages/pa_holt.html  

Uncover more about USF’s early history and the fun, and sometimes curious, events that occurred here by listening to the USF 50th Anniversary Oral History Project, housed in Digital Collections. 

 

Want more USF Curiosities? Check out the posts in this series: 

 

REFERENCES

[1] USF 50th (2006) Anniversary Oral History Project, “Vincent Ahern,” (U23-00002) p. 16, https://digital.lib.usf.edu/SFS0024312/00001

[2] Nancy Holt, Solar Rotary 1995. University of South Florida Institute for Research in Art. http://www.ira.usf.edu/PA/Pages/pa_holt.html

Go Back