The Dome section covers opening and closing of the slit, rotation,
parking, temperature management, and light control.
The historic Lick 36" Refractor is a completely manual
telescope. The dome is also manual. To open and close the shutter/slit
one actuates a switch on the desk console. It is labeled open and
close. There are limit switches so that one only need to move the
switch in its desired position and the shutter will open or close and
stop the motor at the appropriate position.
The dome does not track and needs to be moved manually to keep it
aligned with the telescope. One moves it clockwise or counter
clockwise via one of the two sets of switches. The first set is on the
desk (Figure 1). The second set is on the paddle (Figure 2). The desk
control is a switch that when actuated will move the dome until the
switch is returned to the neutral position. The controls on the
telescope paddle will only move the dome when continuous pressure is
exerted on the button.
The park position of the dome is such that the shutter is pointed
to the east. There is an orange line painted on the moving and fixed
part of the dome (see Figures 3 & 4). Parking the dome within 0.25
meters of the line is sufficient. It actually is desirable to not park
it exactly in the same spot as we have seen the electrical contacts in
the orange high voltage ring/wheel interface degrade causing the dome
to only move in one direction initially.
There isn't any active temperature control for the dome but there
are several things that one should do to manage temperature. First is
to open the dome shutter prior to moving the floor up. The action of
moving up the floor aids in pushing out warm air in the dome. It may
also be advisable to open the windows prior to moving the floor. One
should take measures to keep main building air from rushing in to the
dome floor as it is usually much warmer and will be turbulent. This is
principally accomplished by ensuring both sets of doors are kept
closed.
Dome lighting is controlled by switches on the desk console and by
switches on the east side of the lower door. There is also a dark
screen for the lower door that should be lowered during public
nights.
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