Hi, this is the first light of this new 20" dobsonian scope. http://www.marcoguidihires.com/img/strumentazione/20130709.jpg It is a heavy version of the classical Obsession-like design (except it weighs 130 kg for 0.5 meter aperture). FL is 2000 mm (F/4). Tracking is obtained with a StellarCat without DSC ("easy Tracking" function only). The camera was ASI 120.