The Sony Alpha 7 cameras – especially the 7S and 7SII – are very interesting for astronomical purposes because of their high sensitivity, short backfocus light weight and very compact body dimensions. This very short T-adapter for Sony E-Mount/NEX bayonet, which adds only 8.3 mm onto the 18 mm backfocus of the camera housing, enables an adaptation to all backfocus-critical systems like HyperStar or fast Newtonians.