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Donkeiller

Megrez 90 focuser

18 posts in this topic

Only used my new (to me but second-hand) Megrez 90 a few times.

Great optics but felt that the focusser was a bit "stiff" so today, I made a very minor, less than 1/8 turn (counterclockwise to loosen) of the loading tension adjuster (hex screw M5) following the Williams Optics instruction manual.

It racked out more easily, but then would only rack back 2/3 of the way - at which point it seemed to hit a "stop".

Obviously I adjusted the loading tension screw back to the original setting, but to no avail.

The focuser is now completely inoperative. :bawling:

Surely a minor adjustment like this (according to Williams Optics own instruction manual) should not cause a problem this :D

Any advice would be very welcome.

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I can't help but the number of useless Crayfords out there is incredible. Why do they continue to pump out this stuff? The evidence of the forum and personal experience is overwhelming; cheap Crayfords sometimes work, and sometimes isn't good enough.

Olly

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I managed to adjust mine by virtue of a small thumb screw a small quarter turn was enough to make it almost glide in and out of the tube, sorry to hear of your trouble have you tried loosening it right off and retracting the focuser fully before adjusting back?

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I can't help but the number of useless Crayfords out there is incredible. Why do they continue to pump out this stuff? The evidence of the forum and personal experience is overwhelming; cheap Crayfords sometimes work, and sometimes isn't good enough.

Olly

Olly, I thought that WO were a cut above the average?

People are always raving about WO "build quality".

The focuser certainly appears well-built- steel rather than aluminium.

However I am unimpressed:mad:, I bought it to replace my Synta ED80-

which worked faultlessly...

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Have to say, I find the focuser on my Evostar 80 ED DS Pro a real delight to use. Very smooth and precise :D

Edited by Gina

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Is it one of the newer 90's like this one?

William Optics - Megrez 90 Doublet APO

Make sure the focus lock thumbscrew is backed way out and with the focus/racking tube about half way in, gradually tighten the tension grub screw until it feels about right, through the focusers wheels.

I've had crayfords apart to their individual pieces before. There's really nothing much to them really.

Andy.

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Olly, I thought that WO were a cut above the average?

People are always raving about WO "build quality".

The focuser certainly appears well-built- steel rather than aluminium.

However I am unimpressed:mad:, I bought it to replace my Synta ED80-

which worked faultlessly...

I think the phrase, 'The famous William Optics fit and finish' comes from... William Optics. My experience of their focusers, and that recorded on the forums, is that they are frequently dire and well below the already dismal average. There was that wretched digital thing, for instance, which needed a full redesign. In general WO make their tubes too short, leaving far too much drawtube extended and leading to sag and chip misalignment.

I have a ZS66 and the focuser just manages to hold a mid sized CCD but owners of SBIGs say it won't hold their rigs. Personally I'd like the scope to be less pretty and more functional but I don't want to knock WO too hard, they do some good stuff. Just give us a proper R and P as standard.

I think its simple: you have a smooth metal roller driving a smooth metal strip. Well what a great idea that is!

Olly

Edited by ollypenrice

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Hehehehe. Love reading your fundamentalist hatred of crayfords :)

They're great, in my experience, when used for visual purposes. Easily hold a heavy 2" eyepiece and diagonal.

For imaging, of which I know very little, I do realise intricate focusing is needed, so understand your views. Wonder how the new style R&P W.O. fare to the Crayford stylee?

:D

Andy.

Edited by AndyH
spelling

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i've only come across two decent crayfords for imaging purposes. One are Moonlite Focusers and Two the nice 3.5" crayford on my Altair Astro 115 Triplet.

Edited by Deneb

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A huge focuser obviously designed for a huge scope - what a beauty :) Interesting design :)

I bet some of the expert engineers on here could make a smaller version to suit the smaller scopes most of us use :D

Edited by Gina

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im sick and tired of people attacking william optics and

i wont stand for it :D just joking i think WO

are up their with the best the only one that isn't

is the ZS66 and for 250 euro what do you want.

Edited by John

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dont dare say this scope is not up their with the best :D

post-28694-133877710147_thumb.jpg

post-28694-133877710149_thumb.jpg

Edited by musab

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Is it one of the newer 90's like this one?

William Optics - Megrez 90 Doublet APO

Make sure the focus lock thumbscrew is backed way out and with the focus/racking tube about half way in, gradually tighten the tension grub screw until it feels about right, through the focusers wheels.

I've had crayfords apart to their individual pieces before. There's really nothing much to them really.

Andy.

Certainly looks identical- including the focuser. Only difference in the description is that mine is a f/6.9, the Ad. says f6.2

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Is it one of the newer 90's like this one?

William Optics - Megrez 90 Doublet APO

Make sure the focus lock thumbscrew is backed way out and with the focus/racking tube about half way in, gradually tighten the tension grub screw until it feels about right, through the focusers wheels.

I've had crayfords apart to their individual pieces before. There's really nothing much to them really.

Andy.

Andy, focus lock grub screw removed, racked halfway out and gradually tightened tension grub screw and no joy,

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Andy, focus lock grub screw removed, racked halfway out and gradually tightened tension grub screw and no joy,

Oh pants :)

Anyone out there with a focuser like this one?

I'm just going from memory with crayfords, that were a wee bit different to this one. Wouldn't want to give out duff info :D

Andy.

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There's a guide for setting up the newer type focuser, in the 'files' section of the William-Optics : William Optics Telescope Discussion Group

Hope that helps?

Cheers,

Andy.

Andy, thanks for this advice. However I do not want to sign up to "Yahoo" (bad experience:mad::p:mad:).

Looks like I have to do this to get on the WO Discussion Group.

Any other options?

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