Horizontal Spectrometer Pointing Procedure

As described before, the spectrometers have two horizontally mounted hydraulic jacks to be able to rotate the 'spectrometer proper'. The rotation point is the vertical support hydraulic jack located at the front of the spectrometer (closest to the target). The horizontal hydraulic jacks are mounted at each side of the spectrometer at the back of the dipole. Motion of the spectrometer proper is performed by a manual control hydraulic pump. The pump and associated control are located at the back os the spectrometer cradle next to the cabinets housing the horizontal positioning servoamplifiers. The pump has a three-way hydraulic valve mounted on it. No motion of the hydraulic jacks occurs when the valve is at its center position. The other two positions select the direction of motion for the back of the spectrometer as indicated on the pump (towards the right or left viewed from the back of the spectrometer). The on-off switch for this pump is located in a hand-held unit attached to the pump via a long cable. This allows the operator to observe the dipole motion while operating the hydraulic pump. Two mechanical gauges, located in the vecinity of the hydraulic jacks, are used to determine how much the 'spectrometer proper' has been moved or needs to be moved by the hydraulic jacks.

Procedure

1.

Look at the displacement measured by the mechanical gauges and determine how much does the dipole needs to be moved and its direction of motion.

2.

Select the desired direction of motion by moving the hydraulic valve on the pump to the corresponding position.

3.

Take the pump remote on-off unit and place yourself so that the dipole motion can be observed. Activate the pump until the desired dipole position is achieved.

4.

Return the hydraulic valve to its center position.