LRS Micro-g LaCoste FG5, Manual, Page: 67 / 149

Adjustment and Maintenance
4
10. Block the test beam (push in test beam blocker) and pull out the reference
beam blocker.
11. Translate the fiber optic input until the beam is centered in the fringe viewer
and tighten the screws.
12. Focus the telescope crosshairs and adjust mirror # 3 until the reference beam
is centered in the telescope viewfinder.
13. Re-verticalize the beam.
14. Check to see if the reference beam is still centered in the fringe viewer. If the
beam is not centered, repeat steps 8-14.
15. Place the superspring alignment fixture (pigsnout) over the top superspring
window. Orient the alignment fixture so the two alignment holes are parallel
to the telescope axis.
16. Verify that the beam is traveling properly through the superspring by making
sure the beam enters and exits the superspring through the two holes in the
alignment fixture.
17. If the beam is not traveling properly through the superspring, verify that the
reference beam is centered in the fringe viewer, and verticality is correct.
18. Using mirror # 2, make the test and reference beams coincident in the
collimating telescope.
19. Use the translator plate (twiddler) to align the test and reference beams in the
fringe viewer.
20. Remove the dropping chamber and dropping chamber tripod from the
interferometer base.
21. Block the test beam by pushing the beam blocker in.
22. Remove screws that attach the small plate to the back of the interferometer
base. See Figure 4-2, APD alignment adjustment access.
4-11