SF AST (NVA battery commander's telescope) 10x45
SF means "ScherenFernrohre". Developed in WW 1, the SF was also used in WW2 and this one was made in Poland and used by the NVA= National people's army of the former DDR and other troops of the Warsaw treaty armies.The rain protector tubes are installed on this SF. SF's could be mounted on a tripod or on a tree screw.
This SF can be used as a periscope, but with the legs horizontal you have a better sight on the target. And you can protect yourself against projectiles by hiding behind a tree.
This apparatus is not an Artillery rangefinder. It's just a telescope/periscope!! With the tubes down, the view has more depth.