Classic 8 w super polaris $150.00 garage sale find

Hi All I found a great looking SPC8 for 150.00 at a garage sale! the tripod is the wooden one with the vixen super polaris w slow motion controls all is in nearly scratch free condition I was told it was her ex-husbands So looking down the corrector I see green pellets, and a 2" scratch in the primary that isent to bad looking and mabe a small are where the coating is no more size of a bb, so I've only owned refractors before I don't even know if the focuser is working but do I need to clean the inside of the tube first.. so I get removing the corrector and marking it to exacting standards, but she needs probably a little more than a cleaning. Is this something best left to celestron (aligning optics and cleaning for under 200?? If mice were in there and this thing was taken apart and put back together pre my purchasing I would be concerned because I didn't do. There are tons of forums on maintenance I inclined to do it myself but I hear removing a corrector is one thing the primary is a hole other issue.

Jeremy, I have the same setup. If you are good with removing the corrector, taking out the primary is not much harder. First thing, remove the focus knob (should be a little set screw on it.) You will then see the focus threaded shaft and there will be an E-clip at the end of the thread (or possibly a screw/washer) and this needs to be removed. This will allow the shaft to move through the bearing assembly. Inside the OTA you will find an O-ring or C-ring on the central shaft above the moving assembly that is used as a safety catch. Remove that. With the scope tilted just slightly above level and firmly set in place, turn the focus knob so the shaft goes all the way in. You can carefully grab the central hub to hold the mirror assembly as you release the shaft. Once released, you can carefully pull the assembly out and once free of the shaft tilt it to allow the mirror to pass through the 2 notches in the corrector ring. Once out, you can examine/clean the internal assembly. You may want to lookup some of the sites dealing with removing and relubing the focus assembly, as that reduces mirror flop/focus shift. You don't want to remove the mirror from the hub. As to alignment, the mirror can only go back in one way. If you question the corrector rotation, you should see a line on the back/side of the mirror (usually opposite the focus threaded shaft) that should line up with the serial number engraved on the edge of the corrector (it is small, there may be a line on the edge of the corrector at it as well). If these don't line up when putting it all together, then yes, someone may have gotten it out of whack. If you look at the secondary holder with the cover removed, you may see part of the line on the back of the secondary that should also be lined up with the other marks.
Re-assembly is also easy, if you want, you can release the 3 screws holding the focus knob assembly so that lining it up for mirror replacement is easier. You can then thread the bearing on after the mirror is in place and front retainer replaced. Once the focus assembly is threaded back on, make sure you replace the E-ring or screw/washer to prevent it from ever going in too far. If you take the 3 screws off, you may have to carefully adjust them so that the bearings don't bind. Sounds tricky, but it really isn't.
Good luck,
Brian