Sundials - World's Oldest Clocks

North American Sundial Society

Solar Alignments

Ancient stone alignments and shadows

The heart of the Cosmic Room is an unusual vertical meridian sundial created by sunlight passing through a slot on the roof above.  In winter the solar meridian transit is labeled  with a column of blue tiles and at the spring equinox the tiles change to orange.  The sign "Analemma 12:45" indicates civil time on the spring equinox when the sun is on the local meridian.  With the sun overhead, the beam of light follows the vertical set of tiles downward until it reaches the boundary between orange and blue tiles - the equinox has arrived.  Ruben Nohitol has been photographing this event for the last 16 years, every year since 2002.  From a ceiling hole Ruben marks the image of the sun at 12:45 on the floor with a small green circle.  He does this on dates throughout the year(s), not only creating a nice analemma, but does it with such precision that he is able to notice the slight shifts in solar equinox position through the leap year cycle of four years.

More impressive is the due west sunset on the equinox.   A beam of light streams though a hole in the western wall of his hacienda, across the living room,  through a square hole between rooms, across the Cosmic Room grazing past the vertical sundial and its tiles, and lands as a bright solar disk at the far end of the Cosmic Room on a vertical wood screen mounted on an exit doorway.   To add to the drama of the setting equinox sun, Ruben placed a model of the pyramid of El Cerrito on a shelf in the Cosmic Room blocking some of the sun's rays. The result is a shadow of the the pyramid against the solar disk, giving the illusion of thesun setting over the great pyramid.  You can see his vertical meridian and more at and the sundial in operation at See his patience to photograph the real setting sun over the pyramid of El Cerrito in Queretaro, Mexico at

nass_news_2012_feb_ Nohuitol2_cosmic
[photo courtesy of Ruben Nohuitol]

Ruben Nohuitol of Queretaro, Mexico has a unique solarium or “cosmic room” to observe the rays of the sun throughout the year.  He has patiently constructed a wonderful time-lapse video following the sun every day at 12:45 pm.   His construction has a vertical meridiana beam of light descending and then ascending the wall as time passes throughout the year. A second sky-light gnomon creates a classical analemma on the floor.

Read more: Cosmic Room with Solar Analemma

[photo credit: Andrew Caswell and
Robert Cockburn of The Daily Telegraph ]

Ask a person what is the earliest evidence of humans building structures to mark significant celestial events, and one offer "Stonehenge".  But there may be a structure built thousands of years early according to some experts in Australia.

A site "down under", name Wurdi Youang, estimated to be older than 10,000 years, has a strange arrangement of stones with alignments toward solstices and equinox that has been scrutinized by several eminent Australian scientists.  They conclude that the placement and alignment of the stones is not an accident and there is a perfect alignment with the setting sun on the mid-summer day. Understandably, the exact location of the site is a well-guarded secret, but it is known to be west of Melbourne approximately 80 kilometers.