CORRECTOR REMOVAL PROCEDURE

1.5m Corrector Replacement
--------------------------

Carefully screw two 6-32 threaded rods or 2" bolts into the convex
meniscus lens ring.  Use the 6-32 bolts to unscrew the entire
corrector lens assembly from the barrel (rotate the assembly CCW from
above using the 6-32's).  The plastic retainer ring above the meniscus
lens does not need to be removed to unscrew the lens assembly from the
barrel. Once the retainer is unscrewed and has been pulled out, screw
another two 6-32 threaded rods or 2" bolts into the lens assembly and
lift it out gently.

To reinstall, use the rods/bolts to lower the lens assembly into the
canister, and then screw in the retainer.

Note: The top corrector lens is a convex meniscus lens that sticks up over
0.6 inch.  It is all too easy to accidentally bump its surface, so please
be careful, and wear latex gloves when working with the lenses.

Note: When working with the corrector lens assemblies, please place them
on clean surfaces so that dust does not get stuck to the bottom of the
assemblies (the lenses location is set mechanically).

Nota bene: Once the lens ring is removed, the corrector lenses are
held by friction.  They need to be jiggled carefully for final
removal. Try screwing in 2 more screws in the threaded holes on the
edges, and then rotating the lenses CW and CCW with the 2 screws.