The Building of an Ancient Solar Observatory

by Russ Erganbright


Scattered across Brittany and the British Isles are the remains of hundreds of stone circles created by the inhabitants of the area thousands of years ago. In many cases we can but speculate about how these structures were used in their everyday lives but it’s certainly reasonable to surmise that they had some ceremonial purpose. One thing that is common with many of these structures is they appear to be   solar astronomical observatories, the most notable being Stonehenge built about five thousand years ago on the Salisbury Plain with its alignments to the solstices.


We can but imagine our ancient ancestors watching the sky in astonishment in much the same way as we do today. This was a time when myths and legends held as much validity and meaning to them as does our science of astronomy to us. It would appear that they took great interest in the rising and setting of the sun and the mysterious movement of the moon, planets and stars under this grand celestial canopy that we now call the universe. Their astronomy classrooms were lit by the glow of the campfire with their professors being the elders of the clan passing on their wealth of knowledge by word of mouth from multigenerational observations.


To some the building of the La Veta stone circle to mark the passing of the seasons in today’s world might seem like a superfluous exercise. After all, if you have an interest in knowing when the seasons are going to change there are many sources that require way less energy to obtain than building an observatory. However, don’t we owe it to ourselves to see from where our ancestors have come to help us understand where we are headed should we be able to avoid destroying ourselves with the sword of technology. It’s my firm belief that mankind’s ultimate destination is the stars!


Project Goal

It is our goal to build a simple naked-eye solar observatory at Southern Colorado Astronomy Park from stones and cedar poles that will permit observation of the changing seasons in much the same way people have for millennia.


As an organization SCAS is dedicated to education; in this instance in the form of an open air classroom that incorporates Stone Age technology compared to a modern telescope just begging for youthful eyes to have a gaze. Who knows, perhaps one of these children will find themselves standing on a distant world after having their imagination set ablaze by what we are doing here!



Data Collection and Site Preparation

SCAS was fortunate to receive a gift of 35 acres of property a mile west of La Veta, Co. The property is ideal for an Astronomy Park as it is flat, has a 360 degree unobscured view of the sky and sits above the lights from La Veta. The elevation of the property is 7100 feet above sea level. Access to the site is on a county maintained road. While vehicles travel along the road that borders the property on the north, the property is large enough that telescopes can be placed to the south to avoid their headlights. Simply stated, the sky is dark there. If you haven’t had a chance to visit the site we highly recommend it.


When the construction of the observatory was being considered it was decided to make naked-eye observations at the site on and around the days of the solstice and equinox instead of relying on computer modeling. While a computer could have easily plotted all the needed alignments, thousands of years ago there was no such option for early astronomers. In an attempt to remain closer to the way our ancestors created their observatories we decided to do the same.


Once the site was selected a 6’ T-post was driven into the ground to act as a temporary marker at the center of the observatory. All measurements and observations were to be made from this point of reference. Starting in 2014 the sunrises and sunsets of the solstice and equinox were noted and T-posts were aligned to the rising and setting sun and were driven into the ground to establish a line of sight from the center post to the horizon. Along these lines, 25 feet from the center of the circle, 4′ wide stone cairns are to be constructed and topped with black pointer stones. Beyond each stone cairn, along the same alignment 20 feet away, will be a 6′ cedar pole set in the ground. In addition, cedar poles will be set at true north and south in reference to the circle.


Upon completion, when viewed from the center stone, the shadow of the cedar poles of the rising or setting sun on the solstice and equinox will transect the rock cairns with their black pointer stones and fall on the observatory’s center stone. In this way the observer will be able to note the passing of the seasons.


Construction Process

The completion of the observatory is projected by the fall equinox in 2016. Achieving this objective is dependent on SCAS volunteers and the availability of donated local stones. If you would like to be part this astronomy project creating a naked eye solar observatory that can trace its roots back before the written word please contact Russ Erganbright at , 303-797-1717, cell 303-921-5605.