Open source code for the maths behind a heliostat?
I wrote the source you need some years ago:
https://jumpjack.wixsite.com/progetti/sorgenti-ipsun
The Arduino/Processing version was just a demo program to manually control a TENVIS camera by multiple buttons, it lacks the &quot;astronomical algorithm&quot;.
The Javascript version contains astronomical calculations and a demo page which connects to a local TENVIS camera.
I also built a prototype...

https://jumpjack.wixsite.com/progetti/ipsun
...then I found, at MakerFairRome 2016, a maker which sold on Kickstarter a ready-made heliostat, initially named &quot;Lucy&quot;, then renamed &quot;Caia&quot;... but 5 years passed and it has not yet been born... so I think I'll have to go back to my project and develop my own heliostat.
But in the meantime I found this page about a &quot;static heliostat&quot;, and now I am trying to reverse-engineer it to figure out if it could be easier/cheaper:


http://cleardomesolar.com/solareflexpanels.html
Additional resource with dozens of links to heliostats, coelostats, and whatelse...:
http://www.redrok.com/main.htm#gsc.tab=0