coma corrector stuck in vixen focuser - how do I remove it?

[h0ughy]

I have just received my new scope from a member of IIS and for some inexplicable reason the coma corrector is jammed in the focuser and will not budge? How can I remove it without damaging either the scope or the focuser or the corrector????

[casstony]

wild guess: remove the focusser from the scope and warm it to say 50 degrees in an oven in the hope that differential expansion in the metals will loosen the corrector?

[Dennis]

Is this a VC200L or RS200, where the corrector unit screws into the focuser with a Vixen proprietary thread?

Cheers

Dennis

[h0ughy]

will take some images

[h0ughy]

would cooling it with a CO2 dust remover spray work?

[JohnH]

If it is a VC200L - leave it !! The field flattener is integral to the draw tube and the optical design...I have no idea what would happen to the image quality if it were removed but it would not be good.

[mill]

Hammer and chisel? :)
Cooling it will just make it harder to remove, try a little bit of CRC.

[h0ughy]

its a R200SS

[h0ughy]

not near optics - ever

[mill]

just joking.
A little crc should do it.

[Dennis]

Dave

The VC200L is a 200mm F9 cat with a multi element corrector built into the focus tube/baffle inside the OTA so I was referring to the optional external F6.4 Reducer which screws onto the focuser outside the OTA, at the back end like an SCT.

The R200S is an 8" F4 Newtonian (focuser on side of tube).

Is it one of these? Or none of the above?

Cheers

Dennis

[casstony]

http://www.buytelescopes.com/manufacturers/vixen/pdf/VixenNorthAmerica_R200SS_ComaCor.pd f

[h0ughy]

this isthe scope and focuser

[casstony]

Absolutely it would, but I would heat it first and then hit just the corrector with the CO2. It's great how, when you're in a pinch, you can come here and get so many useful suggestions :)

[h0ughy]

post no 8:D :P

[alan meehan]

maybe try warming it with a hair dryer then try to unscrew it,it should just screw in.

[Omaroo]

David - if you remove the whole focuser from the OTA, are there a couple of opposed slots cut into the corrector's periphery onto which you might be able to get a blade across from the inside? Maybe it was fitted off the OTA - in reverse, for some reason unknown. Seems weird, but you never know....

[Dennis]

Dave

I have a VC200L and by unscrewing the 2 screws on the R&P focuser, I can slide the whole focuser assembly out of the focus tube attached to the OTA. Careful of the grease on the rack. Looks a beautiful ‘scope by the way.

Cheers

Dennis

[RB]

That's a bit disappointing Dave, hope you sort it out.

:sadeyes:

[Dennis]

Your fine illustrative photos look a little dark Dave, with blocky shadows - obviously taken with the Canon and not the Pentax eh......:P ;) :whistle:

Cheers

Dennis

[h0ughy]

yes I asked Mr persuader to come out and play with it. Should have done that in the first place. but I wanted to be gentle and take the smooth and subtle route - doesn't suit me for some reason? thanks for all the advice:lol: :lol: :lol: :P

[wavelandscott]

Gotta love Mr Persuader!

[RB]

Mr Persuader should've been included in the package. :P

[h0ughy]

I think Mr Persuader will be visiting SPSP;) , he just loved large aperture telescopes - like Rodstars:D :P :whistle: even 12" dobs, Taks and other refractors;) . he doesnt like to get angry, you would like him when he is mad:rofl:

[Don Pensack]

Why remove it? an f/4 scope absolutely needs one for coma-reduced images.
Is it tilted?

[h0ughy]

1. needed a clean
2. I mistakenly though I could add 2" Ep right away, but as I have found out that is a vixen add on
3. I had just received the scope and wouldn't you be very curious to inspect the focuser and the connecting parts?
4. because I am a newbie when if comes to a newt. I was very gentle only needed to just a little leverage, it then freely unscrewed. Up until that point however no amount of hand torque was budging that sucker

oh and the collimation

[sejanus]

I'm surprised it was so tight for you. as i said on the phone, a finger down the barrel for me then pressing against the side was enough torque to pull her out. I'm not doubting what you are saying, just struck me as odd!

[h0ughy]

Struck me as frustrating :rofl: :D

[Dennis]

Must be a Vixen thing. :shrug:

When I received my VC200L, it came fitted with a black anodised extension tube on the focus tube. It took quite a lot of brute strength to unscrew this so I could use a star diagonal.

I think the threads are 60mm?

Cheers

Dennis