failed step 2!

[blink138]

hello peeps, i have finally plucked up the courage to remove the corrector from my fastar c11cf as my secondary baffle is freely rotating in the corrector and after it happened i don't seem to be able to collimate the scope
i have been researching it a fair bit over the last few weeks

however ............ after removing the retaining plate screws i cannot remove the retaining ring ffs so i am scuppered at the second hurdle!

any tips or hints on this?
pat

[Zuts]

I don't believe it is glued on. I would remove the corrector and then twist while holding the retaining ring in front and the secondary behind. The corrector is sandwiched between the holder and ring. Applying force to the ring while holding only the holder and ring should not damage the corrector.

[multiweb]

Drop a bit of acetone with a syringe around the rim, get a big flat screw driver and pop it. Mark it so you can put it back in place the same way and remember which side faces out.

[Dave221]

I managed to free a stuck corrector plate by attaching a 50mm suction cup, after making sure the surface was clean so that no scratching occurred. It provided enough grip to gently free the plate.
This might seem a bit drastic but it worked and there was no evidence of the attachment point on the corrector plate after I cleaned it.

[Zuts]

He has already said that the holder rotates around the corrector so it's the ring that is stuck to the holder and not the holder stuck to the corrector.

[Zuts]

Unless he means the large corrector retaining ring and not the holder retaining ring, in which case I am completely of the mark :shrug:

[blink138]

thanks guys .............. yes i cannot remove the retaining ring
i have removed the eight screws to the ring, but the ring will not pop out so i can then remove the corrector ........ arrggh!
pat

[blink138]

after looking at all the youtube videos, after removing the eight screws holding in the corrector retaining ring the ring just comes out! but i cannot seem to budge it
pat

[blink138]

the offending immovable blasted ring!

[blink138]

the spinning secondary (the problem i want to fix)

[blink138]

i can get a credit card in around the whole perimeter, but it will not come out!

[multiweb]

You need to wet between the corrector glass, the corrector cell and the retaining ring with a bit of acetone. Is your retaining ring PVC or alu?

Jam a flat screw driver under the retaining ring to pop it. When done mark your shims and corrector orientation. The take the shims out, jam the screw driver between the glass and the corector cell and twist to get the glass unstuck, then remove it and clean it. It's due for a wipe too by the look of it :)

[blink138]

ok mark i can do that
aluminium
so the screwdriver between the outside of the retainer and the wall of the tube? no possibility of damage you don't reckon?

[multiweb]

It's glass so don't hit it but you won't scratch the edges. What's under the retaining ring is probably full of crap and it's not in the optical path so don't stress about it. Pry it open. Make it move sideways first then lift it. The acetone will dissolve all the crap that "glues" it. The bits you don't want to damage are what your mirror sees. When you tighten your secondary cell make sure there are cork or rubber gaskets on each side and don't overtighten it in the glass. Most importantly don't tighten too much the retaining ring when you put the corrector back. Just touch. No pressure. Or when your scope goes from hot to cold and vice versa you'll split it in half if it hasn't room to breathe.

[blink138]

so mark you are saying lever the screwdriver between the corrector and the retainer? ............. scary lol! not wher i put the credit card in the pic above?
i have just come back from my work where i have acetone and a glass eye dropper ................. here goes!

[blink138]

success mark!
corrector a bit stuck now!

[blink138]

hmmm the corrector has not got an even gap all the way around?
can't put a credit card in the gap at the bottom
more acetone to unstick the corrector mark?

[multiweb]

yep, let it soak a bit. is there room for a small flat screw driver head to stick in and twist gently?

[blink138]

still no luck with this one, i tried standing the telescope vertical and done the acetone, let it soak for a while but it still won't budge
now i have acetone streaks on the inside of my corrector, i hope that it does not etch into the multicoat
must admit i am very scared about using the screwdriver as leverage
pat

[multiweb]

You need to do that with the corrector horizontal so scope facing up and get the corrector unstuck. If you have acetone on the glass corrector I'd get it out asap now and wipe it out quickly.

[Wavytone]

Tried paddle-pop or icy-pole sticks ?

[blink138]

good idea that!
pat