The image above shows the 32-inch telescope and the dome's slit in the background.
The fork mount extends down to the right and the truss frame "tube" are the white pipes extending, angled upward, where they attach to a support ring that carries the secondary mirror.
At the bottom, there is usually attached some kind of instrument, such as a filter wheel with attached CCD camera (for direct imaging), or a spectrograph, with another CCD camera.