What is a Newtonian binocular telescope?
It’s a reflecting telescope with two Newtonian optical trains, arranged so the two eyepieces are next to each other. Two telescope configurations are typically used: side-by-side or stacked vertically. Side-by-side requires extra diagonals to make their focal planes available. Stacked vertically, the bottom telescope’s secondary must be positioned closer to the primary for the same reason. In side-by-side configurations, you look towards the primaries with your back to the object. In the stacked approach, the eyepieces are located in the typical Newtonian fashion along the side of the tube perpendicular to the primaries’ optical axes.
