Need some idea`s

[nightfisher]

I would like to rig up a better focuser for my Vixen VMC110, it is so very sensitive that just trying to touch it shifts the focus, at present im toying with rigging some motor drive, maybe on the line of the x2 radio control servo system with a belt, i do have a skywatcher focus motor but thats going on my 150p ds some time soon, i need to work out how to remove the black focus knob on the rear, this will allow me to add some fibre washers beneath the knob to add some extra tension, this alone might work and be good enough but really looking for some useful idea`s here, toyed with adding a Borg helical focus  but i am pretty sure this will add to much out focus to the unit

[nightfisher]

Sorry to bump this but could really do wit some idea`s on how to improve this focuser

[Moonshane]

hi Jules

I have heard of people adding a peg to this sort of focuser to create a larger circle. might work?

[nightfisher]

cheers Shane but thats not really the problem, its more like mirror flop, a really slight touch on the focuser seems to make the focus jump, seems there is a good scope being let down on this issue, hence my thinking about some kind of motor and belt

[Steve Ward]

Can you not fit another focuser to the back as we did on the Mak180 , there should be plenty of adjustment in the main focuser to account for it ... ?

[nightfisher]

no Steve, it is 1.25 back, i thought about a borg helical but this would extend the light path and it does not  have the huge focal range of a normal mak, so looks like it has to be  motor to the factory focus dial

[Stu]

Can't remember Jules was this a new purchase or used? Do you know if this is a normal problem or something which can be serviced by Vixen?

Are you talking about image shift, or that you can't get accurate focus?

Sent from my iPhone using Tapatalk

[faulksy]

might help, my celestron 9.25 used to have some mirror flop. i striped it down and lubed the centre tube with dow corning vac grease, i found the mirror tube was causing a bit of stiction, after this mod there was no issues at all

[nightfisher]

looks like i will have to strip it and see if i can fix it but looking at doing a servo motor mod to it

[michael8554]

Found this image of the VMC110.

I'm not familiar with the scope, does the visual back unscrew to allow a Crayford focuser to be added without extending the light-path too much?

[AndyH]

Looks like the back unit comes off easily-ish. Some nice pics of the internals,

As mentioned above, a clean & re grease of the sliding baffle, may help cure at least some, of any focus/mirror shift.

I think many folk with moving mirror systems, recommend reaching best focus from the outside-focus up, rather from inside-focus back, if you see what I mean? ie: So you're pushing the primary up the sliding baffle tube. I've read this lessens any potential mirror wobbling.

Andy.

[nightfisher]

Andy, thanks for the pics, looks like the end screws of the tube to get to the mirror and other bits inside, i will take it apart later on and see what can be done, i had got to thinking i might just sell it but i want to stick with it, the optics are good and its a nice wee scope that works well on the AZ super track mount, so its time to fix it 

[philj]

Some decent viscocity silicon grease just to stop the flop is the answer, a motor drive on its own wont really cure it.

[nightfisher]

Some decent viscocity silicon grease just to stop the flop is the answer, a motor drive on its own wont really cure it.

I think you may well be right matey, also i am at a loss as to where to locate a motor on the scope, will just go with opening it up and try to improve things inside

[skybadger]

Interesting, I haven't really noticed this as a problem in mine. The focus is very sensitive though. What about an sct 10x focus reducer ?

Mike

[nightfisher]

Interesting, I haven't really noticed this as a problem in mine. The focus is very sensitive though. What about an sct 10x focus reducer ?

Mike

Yes, VERY sensitive, having just opened it up, i can see darn near no flop or unwanted movement on the mirror, i think a drop of Moly grease on the central tube will help as this seems to have just a thin oil on it from factory, and i think i will go with the servo focus, this mod will cost pennies to do, i have one modded servo and some belts so just need another £4 servo 

[Moonshane]

it seems similar to the flop/lag in a cheap rack and pinion?

[nightfisher]

it seems similar to the flop/lag in a cheap rack and pinion?

maybe not, there seems no unwanted movement in the system, my first thought was as skybadger says, just VERY VERY sensitive, hence my idea of the servo focus mod

[JamesF]

i am at a loss as to where to locate a motor on the scope,

Could you use one of the existing mounting points to fit a bracket to carry the motor?

James

[nightfisher]

Could you use one of the existing mounting points to fit a bracket to carry the motor?

James

Yes i could make an Ali bracket to mount the servo and fit it to the spare dovetail mount area, for some reason i ruled this out at first

[wenrongc]

I have the same VMC 110 and experienced the same focusing issue. I just find a very easy way to fix it. 

(1) get rid of the plastic focuser knob, just pull it out by force.

(2) You will see the focusing stick.  There is a ring at the base of the focusing stick. The ring has two grooves allowing you to rotate it. 

(3)  To tight the focuser. Rotate the ring clockwise, to loose it, rotate it counterclockwise. 

(4) Put the knob back then done. 

I fixed mine within 5 min. Now I have a very nice focusing. 

Hope it helps! 

[nightfisher]

I have the same VMC 110 and experienced the same focusing issue. I just find a very easy way to fix it. 

(1) get rid of the plastic focuser knob, just pull it out by force.

(2) You will see the focusing stick.  There is a ring at the base of the focusing stick. The ring has two grooves allowing you to rotate it. 

(3)  To tight the focuser. Rotate the ring clockwise, to loose it, rotate it counterclockwise. 

(4) Put the knob back then done. 

I fixed mine within 5 min. Now I have a very nice focusing. 

Hope it helps! 

Thank you for the tip, i have seen this ring, i will be taking it apart again soon as i have now voided the warranty and doing this mod along with some moly grease on the mirror shaft