thanks Marty,
i gone order that book to understand more of it, so that i know what i am doing
for me it’s a little bit confusing that the angle is south and north
but if i am right it’s gone be ask more calculation due to the ideal angle from 58° to 106° all over the year
but right now from what you said about 10° maybe i gone do it with a butterfly roof at that angle from 10°and panels on both sites
cheers
Marc