U.S. DEPARTMENT OF THE INTERIORBUREAU OF LAND MANAGEMENT
 
BLM Colorado | WRFO Cultural Resources | Canyon Pintado National Historic District | Sun Dagger Site
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Winter Solstice

This first series shows the shadow created by the overhang consuming the smaller circles to the left, right, and top, leaving the central spiral illuminated by the sun at approximately 9:40 to 9:45 am Mountain Standard Time on 12/21/2009 (Winter Solstice). A dagger of shadow appears to pass near the center of the spiral around this time.

Winter solstice 

Summer Solstice

The second series shows the progression of the shadow across the spiral and concentric circles on 6/21/2010 (Summer Solstice). The shadow’s line crossed the center of the spiral at 8:31 am Mountain Daylight Savings Time. Did Archaic-period or Fremont people use this phenomenon to determine the day of the solstices, or are the observed interactions purely coincidence? More data is required to test ideas of the site’s possible solar interactions, and we may never have a definitive answer as to its purpose.

Summer solstice 

Future photo series will show what, if anything, happens during the Vernal or Autumnal Equinox and midpoints between the equinoxes and solstices. This data will help us determine whether or not the Sun Dagger site in Canyon Pintado was a solstice marker and how it may have functioned.


 
Last updated: 03-20-2014