Here is my page dedicated to info on the secondary mirror and corrector plate of the LX200 telescope.

To properly see how things are put together, we must remove the corrector plate from the OTA. While not for the faint at heart, it is actually a fairly simple process. Just be careful and pay attention to detail!

Attach the scope to a stable surface (the tripod works great) and position scope so secondary end (front) of OTA is slightly above horizontal to keep the corrector from falling out during later steps (see image below).

Remove the 6 hex-head screws that hold the secondary retaining ring in place. The only thing holding the secondary in place is friction caused by this ring so proceed with caution after removing the last couple screws. The screws are evenly spaced around the ring just inside the front rim of the OTA. The retaining ring is the plastic part with the raised white lettering on it. Remove this also.

PICTURE OF RETAINING RING OFF

Note the index mark that shows the alignment position of the secondary in relation with the OTA (and thus the primary). This mark is very important to the optical health of your scope. Do not remove this mark and ensure it is lined up properly when reassembling the scope. Make one with a dab of 'correcting fluid ('Whiteout') or paint if you don't see one or if yours is chipped or hard to see.

CLOSEUP OF INDEX MARKS

Under the plastic retaining ring is the edge of the corrector plate. Note the small cork pad near each or the retaining ring screw holes (see image below). These pads keep the corrector plate centered in the end of the OTA. These pads can become permanently compressed with age and your corrector may have a bit of side-to-side play at this point (grab the outer secondary housing and try to move the corrector perpendicular to the OTA in all directions. If you have slop here, new cork pads or a bit of thin cardboard can shim up the corrector position. One wants just enough tension to keep it from wobbling around, yet not too much to put stress on the glass.

On my scope (see image above) I had some play here. You can just see the gap between the corrector plate and the cork shim. It was about a 1/16" space but gave the feel of a much larger gap when the plate was moved side-to-side. A couple of cardboard shims as described and things are snug now.

Below is a picture of the corrector being removed from the OTA. If this is the first time, the corrector may stick a bit. There is nothing holding it in but age at this point, so work it slowly side to side and pull gently away from the OTA while grasping the outer secondary housing. Slight pressure with a wooden tool around the edge of the corrector may help - but be gentle! You will feel it pop free after a while. Carefully remove the corrector by pulling it away from the end of the OTA. Remember that the secondary mirror and inner housing stick out quite a bit on the inside surface, especially on the f6.3 version.

Here we have a corrector completely removed. Not the relative dimensions of the parts from left to right: outer secondary housing, corrector plate (about 1/4" thick), and inner secondary housing. In the image below, the inner housing has already been flocked. Note the vast improvement in glare and reflectance, even while shining the camcorder light directly on it.

The inner secondary housing is a thin plastic shell that is merely screwed onto the outer housing where it protrudes through a hole in the corrector plate. My entire secondary assembly had movement in it (found this out when it started spinning while collimating one day). Tightening this connection will keep the secondary from rotating freely. If completely unscrewed and removed (there is a thin paper gasket also), you will see the interior assembly of the secondary as shown below.

Note at this point there is nothing holding the corrector plate to the secondary housing except gravity. Hold the assembly in the configuration shown until you are ready to remove the corrector plate as it is just sitting there loosely now.

Not being a telescope maker, I was surprised by the thickness of the secondary mirror - almost 3/4". Note in the image below how the assembly is joined together. Collimation screws are visible, as well as the plate holding the secondary.. Close-ups of each piece follow.

The corrector plate is now removed by lifting it over and off of the secondary mirror (The central hole is just big enough). Set it aside for safekeeping. It is matched to the primary and if damaged or destroyed, will require complete replacement of the optical train (about $1500 USD last I saw a number).

The secondary assembly disassembled - removing the 3 collimation screws is all that is required.

The mirror is attached (glue?) to an aluminum plate.

The bottom of the plate is bored for 4 holes, 3 threaded for the collimation screws, and 1 for the central pivot

Those who have wondered what might happen if they cranked down on the collimation screws too hard ay sleep better knowing that they have to bend a thick aluminum plate to start doing any damage.

The mirror/plate combo sits on top of a 3-vaned extruded aluminum spacer that has 3 slots for the collimation screws to ride in, and a central pin that the mirror/plate balances on for collimation. Note the 3 small metal washers sitting atop the central pin. There are no washers where the collimation screws go because the two surfaces don't actually ever touch (see images below).

The outer secondary housing is just a molded plastic casing with 3 holes for the collimation screws to pass through, and a threaded rim for the inside housing to attach.