The Holzer Polar Dial showing seven p.m. in the evening on the polar ice in February of 2009
The Holzer Polar Dial
The Holzer Polar Dial is an object that allows you to explore the relationship of your relative location – be it your backyard or the planet you are spinning on – to the nearest bright star, the Sun.
I would like to define the parameters of tolerance in the arrangement of the Holzer Polar Dial. Levels of accuracy in this context are very much like chasing zero – a road all it’s own – as the idea of the dial is to heighten one’s awareness of place, the location, and it's relationship to the Sun on our planet, spinning in space, in the company of what would at least appear to be fixed stars. Ever finer degrees of accuracy are best arrived at empirically.
We are moving; the stars are passing by overhead.
The Holzer Polar Dial is an equatorial dial, with line AB parallel to the equator and the plane of the dial plates at right angles to the equator. The dial plates are numbered with the hours of daylight. For this installation, I have made a dial that will read all twenty-four hours of potential daylight in the southern latitudes. The Gnomon casts a shadow on the dial plate and the Sun’s shadow travels through the hours. At the hours of twelve (both a.m. and p.m.) and six (a.m. and p.m.), the Sun’s shadow can be read on the dial plate that the shadow is leaving as well as the dial plate that the shadow is beginning to travel through.
I have oriented the dial to be parallel to the equator by establishing the co-latitude, which is found by subtracting the local latitude from 90° . The co-latitude for this location, 71° South, is 19° . (90° - 71° ) = 19° . This orients the 8″ x 8″ equatorial plate parallel to the equator with the dial plates at right angles to the equator.
Pointing the north mark of the equatorial plate at the pole star, or in this case (Southern Hemisphere) with a compass to north, aligns the dial to read Solar Time, Local Mean Time. For the sake of this installation, we shall set the dial by pointing it appropriately north and setting the dial with a clock set to Greenwich Mean Time. As the location is at 2° of longitude west, which equates to about 6 minutes, it is accurate enough for general observation of the hours of sunlight.
The Holzer Polar Dial is a unique design, one that I have been exploring since 1982. The dial has been made in several versions, from different materials, cast and fabricated, and installed in various locations. I would like to acknowledge a debt of gratitude to Albert E. Waugh for his book "Sundials: Their Theory And Construction."
You can see the Holzer Polar Dial installed in Antarctica by visiting Erika Blumenfeld's Polar Project site.
For information about site specific installations
432-295-0075 (Central Standard
Photos courtesy of Erika Blumenfeld