Here is the reproducibilty of the parallelism of the Center Mount by the movie.
The Center Mount is not the mere mount but a core part that will make a pair of the OTAs into a Binoscope. You can also say that this mount is a part of a binoscope.

中軸架台の（鏡筒把握の）平行度の再現性を示す動画です。　この中軸架台は、単なる経緯台ではなく、BINOの構造部の要を担うパーツでもあるのです。