The floor moves up and down to accommodate viewing. It moves up and down via hydraulic pressure on several telescoping pistons. They are actuated by electronic controls on the telescope paddle and the desk console. The floor is original with a ratchet safety system.
When the ambient temperature is cool it stalls near the top as the final rams extend to push the floor its final couple yards. The approximate maximum number of people on the floor is 12. It is advisable that people on the floor do not stand in the same location near the edge of the floor as a slight tilting of the floor can occur causing it to jam.
When the floor is at the top one still might be required to use ladders for viewing (for example when viewing the Trifid Nebula at -3 Hour Angle). When the floor is at the bottom one can observe at zenith while seated in a chair. The floor is stowed at the bottom as shown in Figure 1. Figure 2 shows an example of the floor at a mid level, where climbing down the stairs and hopping over the railing is necessary to access the floor. Figure 3 shows floor at the top. Figure 4 shows the bar clamp in the open position which allows one to open the railing for crossing.
There is a safety strip the cuts off power to the entire control system if someone touches it, shown in Figure 5. It keeps people from accidentally getting sandwiched between the moving floor and the upper level. When someone hits this strip the floor stops and control power must be turned back on at the desk console.
To move the floor one can command the floor up and down from two places, the desk and the telescope. The desk buttons are up, down and stop. Once pushed the floor will continue until it hits a limit or the stop button is pushed. From the telescope, the buttons are on a paddle and will move the floor until they are released. If they get stuck it is possible that one will have to stop the floor from the desk.
For safety the railings should all be closed and latched in position before moving the floor a significant distance. During observing, one will have to move the floor small amounts periodically to keep the eyepiece at a comfortable viewing height. Make sure that no one is climbing on or off the floor before moving the floor. Also, make sure that no open railings bridge the gap between the moving floor and the catwalk or lower floor as the railings can be damaged when the floor moves.
Figure 1: The floor down in the proper stowed position