My favorite star of all

     I became a Mechanical Engineer largely from my interest in solar energy, the environment and a desire to travel the world. I volunteered for a number of interesting projects, but I am most proud of my years of work with Solar Cooking. I designed cookers, wrote, spoke at conferences and did early work on some significant field projects. My Masters degree project was the design of a cheap, lightweight easily deployable solar cooker for disaster relief. I was part of the team that designed the Solar Cookit, shown in the adjacent photo. That design was immediately released to the public domain so that anyone could produce it freely. Over 20 years later that cooker is still in production and in use around the world. I'm still incredibly proud of that little cooker.

     Most people don't realize it is possible to cook the basic foods of most of the Earth's population with simple solar devices. At nearly a kilowatt per square meter, the incoming solar radiation has a HUGE potential for good. Rice, beans, breads, stews and many other staples can be easily cooked without fuel, fires or smoke inhalation. It works for two meals a day, and hundreds of days per year. It is equally easy to pasteurize water, eliminating a primary cause of disease among the half of humanity that does not have access to potable water. HALF! Think about that for a moment. Then go to: www.solarcookers.org and support their tremendous efforts with real star power. 

     My work in Africa and Latin America affected me in too many ways to explain here. Some of the things I brought home were a high respect for those who live in harsh situations, an appreciation for simple living and a decent ability to track the Sun and celestial bodies. Later on, while living in and travelling throughout Europe I became enamored with the large public sundials in every little town. 

     I don't know how many times I've  said "Someday, I'm going to make my own sundial". Well, someday finally arrived and that's where this silly project comes in ...    

     In early June of 2017 I fabricated a gnomon for my latitude, sized for the largest patch of Southern exposure on the house. I put a starburst shape at the tip with a half inch hole in the middle. This gave a well-defined point of light in the middle of a star shaped shadow.  

    By June 21st I was ready to start marking the shadows’ path across the wall at 15 minute increments. With a Sharpie marker and an accurate time signal I was able to record the marks position through the day. The points plotted out a large frown-shaped curve near the bottom of the wall. Of course the points were marked at the time corrected for our elliptical orbit by the equation of time, not just clock time. Here's how that works: 

   On June 21st, 2017 the correction was  -1 minute and 51 seconds. The negative sign means the Sun was running SLOW to clock time. At clock noon the mark had not quite reached what would become the red noon line. A minute and 51 seconds later it arrives at the correct spot. In this example, the 12:00 mark was made at 12:01:51. Every mark that day was corrected by that same amount. 

    Each month the routine was similar - set alarms a couple minutes ahead of the corrected times and work on other projects around the house. When the alarm rang I’d race out & up the ladder to mark the point at just the right second. On the Autumnal equinox (September 22 that year) the shadow rewarded me with a dead straight line and a simple proof that the Sun was on the plane of the ecliptic. Later months produced smaller smile-shaped curves. Once the data was marked for the Winter Solstice on December 21st, I had the full boundaries of the dial identified.