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Use the template from RGOC position collimator 1 (C ) on the collimator optical axis. Remove R from its baseplate, remove the alignment post from the telescope end of the optical bench, and replace it with a perforated alignment target. The laser beam should now be striking the pole of the front lens of C . Adjust the position of C to get the back reflections and interference patterns coincident with the laser beam at the target. Replace R and check the separation A to the pole of C - this should be 860.5mm. If necessary, adjust by using blocks to allow the complete collimator baseplate to slide along the collimator axis, and further clamping blocks and slip gauges to enable controlled adjustment. Minor adjustment of the longitudinal position of C can be achieved using the micrometer on C , but note this has a total range of 2.5mm, so it is best to put this in the centre of its range, and adjust using the method described above. Remove the alignment post closest to the laser, and replace it with one of the perforated targets. . Iterate on checking the separation between R and C and the back reflections until both are correct.
Use the same method to position collimator 2 (C ). The separation between C and C should be 227.6mm. Remove C to do the squaring on. (note: both at RGOC and when aligned at LPO it was not possible to balance the back reflections and interference patterns from C perfectly -- see figure ?? for details. Again, it is necessary to iterate between separations and back reflections. Clamp the baseplate securely to the optical bench, and lock all adjusting screws on the kinematic mounts.