I made my first astronomic folding home observatory with rotating dome using sufficiently thick waterproof white fabric. During its use I checked indisputable benefits of the observatory made this way. At the same time I was trying to find out what else could be improved further. An important question, I wanted to find an answer to, was how and whether to solve the interior light caused by the casing white colour formed by a single layer of the fabric forming the cover. The conclusion was quite clear after checking various alternatives of the solution. The installation of the second fabric placed inside won as the optimal alternative, although it will increase the physical difficulty of the casing installation by increasing its weight but it will reduce, in a significant way, the spread of parasitic lighting inside the observatory and especially light penetration from outside. I was even a little bit surprised how, from the point of view of the astronomer looking for a dark secluded place in the nature in vain, significant this modification is. I did not give in to the despair any more when, during the time of my observing the night sky from my garden, my neighbour, living close to me, shone a halogen light on his house. And likewise, the flickering of a distant street lamp partly hidden behind a full-grown tree already ended. I could enjoy fully beautiful catches from astrophotography from the deep space available to me.