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 http://www.makeaholeinthewall.com and the sundial in operation at http://www.sundials.org/index.php/dial-links/videos/meridiane See his patience to photograph the real setting sun over the pyramid of El Cerrito in Queretaro, Mexico at http://www.sundials.org/index.php/dial-links/videos/analemmas-time-and-motion