Back reflections

Examples of back reflections from aligning optics.

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Objective 15cm from back

Back reflections from a laser aligned into the back of Nikon 40x0.95 air objective. The viewing screen is placed ~15cm from the back of the objective. Radially symmetric interference rings indicate good alignment:

objective_15cm_from_back_aligned.jpg
Back reflections from a Nikon 40x0.95 air objective (MRD00405) with a viewing screen ~15cm from the back (aligned).

Back reflections on the same setup with some horizontal misalignment (tilt in this case). The interference rings are not radially symmetric, so this is not well aligned:

objective_15cm_from_back_misaligned.jpg
Back reflections from a Nikon 40x0.95 air objective (MRD00405) with a viewing screen ~15cm from the back (misaligned).