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Megrez 90 focuser

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17 replies to this topic

#1
Donkeiller

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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.

Celestron 8SE, 6SE plus Antares focal reducer
Celestron SE Goto
Kson 1026 ED (Carbon Fibre)
Skywatcher Synscan AZ Goto
Various EPs (BST, Televue, TMB, Xcel-LX)


#2
ollypenrice

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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

Run Les Granges Astronomy Holidays, teach and learn imaging, SE France.  TEC140 apo on Avalon Liner FR. 2xTakahashi FSQ106 tandem on Mesu mount 200.  TeleVue Pronto, ZS66, 6 inch achro. Other mounts, Takahashi EM200, 2 x EQ6. TeleVue Gibraltar and TelePod. CCD; 2xAtik11000 full frame, SXVH36, Atik 320E, Lodestar, DMK21. Leica bins. This kit is co-owned owned with Tom O'Donoghue and Yves Van den Broek. Host 4 scope robotic shed. www.sunstarfrance.com

Isn't it great that amateurs can get so close to the universe?


#3
Anweniel

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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?

William Optics Megrez 90, Celestron 7x50 Finder, Skywatcher Skymax 127, Optrons 8" F4 Newtonian
Celestron CG5-GT, Skywatcher  EQ6 Pro
Celestron Eyepiece Kit, 7mm & 10mm Axiom LX
Baader 2", 7nm Ha, 8nm SII, 8.5nm OIII, Starlight Express 5 x 2" Filter Wheel  Skywatcher 2" LP filter, Celestron RGB, Moon, DIY Solar filter
Lx modded SPC900NC. Canon Eos 1000D, QHY5 Mono, ZWO ASI120MC, Atik 383L+, Starlight Express  MX5-C


#4
Donkeiller

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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...

Celestron 8SE, 6SE plus Antares focal reducer
Celestron SE Goto
Kson 1026 ED (Carbon Fibre)
Skywatcher Synscan AZ Goto
Various EPs (BST, Televue, TMB, Xcel-LX)


#5
Gina

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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, 28 December 2011 - 11:20 AM.

Gina
SW Explorer MN190 - Esprit 80ED Pro - Evostar 80 ED DS Pro + 0.85x FR/FF x2 - one with Baader SteelTrack focuser - EQ8 & NEQ6 Pro mounts - Guiding OAG with Lodestar X2 & PHD - Atik 460EX mono x2 and 314L+ mono Filters Astrodon 5nm Ha, 3nm OIII, 5nm SII - Baader LRGB - Atik EFW2 filter wheel - 35, 55, 85, 105, 135, 200, 300mm lenses - EQMOD CdC APT SharpCap DPP DSS PS Artemis Capture


#6
AndyH

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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.
Tal 200K, Tal 2M, Tal 1, Tal M, Tal Alcor, Burgess CaF2/La 90mm Doublet Apo, Carton 60mm F16.7 Achro, PZO T50x70 Maksutov, Dark Star 6.25" F7.7 Newt/Dob
Eyepieces, mounts n stuff

Albums - http://stargazerslou...user/381-andyh/

#7
ollypenrice

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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, 28 December 2011 - 11:35 AM.

Run Les Granges Astronomy Holidays, teach and learn imaging, SE France.  TEC140 apo on Avalon Liner FR. 2xTakahashi FSQ106 tandem on Mesu mount 200.  TeleVue Pronto, ZS66, 6 inch achro. Other mounts, Takahashi EM200, 2 x EQ6. TeleVue Gibraltar and TelePod. CCD; 2xAtik11000 full frame, SXVH36, Atik 320E, Lodestar, DMK21. Leica bins. This kit is co-owned owned with Tom O'Donoghue and Yves Van den Broek. Host 4 scope robotic shed. www.sunstarfrance.com

Isn't it great that amateurs can get so close to the universe?


#8
AndyH

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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, 28 December 2011 - 12:27 PM.
spelling

Tal 200K, Tal 2M, Tal 1, Tal M, Tal Alcor, Burgess CaF2/La 90mm Doublet Apo, Carton 60mm F16.7 Achro, PZO T50x70 Maksutov, Dark Star 6.25" F7.7 Newt/Dob
Eyepieces, mounts n stuff

Albums - http://stargazerslou...user/381-andyh/

#9
Deneb

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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, 28 December 2011 - 12:25 PM.

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#10
johninderby

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I wonder how well the Clement " Bellerophon" focuser works? Although it wouldn't fit too well on a Megrez 90 though. :D

http://www.clementfocuser.com/

John

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  • 500_3.5inBellerophonwith3.5to2i.jpg


#11
Gina

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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, 28 December 2011 - 12:59 PM.

Gina
SW Explorer MN190 - Esprit 80ED Pro - Evostar 80 ED DS Pro + 0.85x FR/FF x2 - one with Baader SteelTrack focuser - EQ8 & NEQ6 Pro mounts - Guiding OAG with Lodestar X2 & PHD - Atik 460EX mono x2 and 314L+ mono Filters Astrodon 5nm Ha, 3nm OIII, 5nm SII - Baader LRGB - Atik EFW2 filter wheel - 35, 55, 85, 105, 135, 200, 300mm lenses - EQMOD CdC APT SharpCap DPP DSS PS Artemis Capture


#12
musab

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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, 29 December 2011 - 04:52 PM.


#13
musab

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

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  • flt132_01.jpg
  • tel_flt132_f1b.jpg

Edited by musab, 28 December 2011 - 04:42 PM.


#14
Donkeiller

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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

Celestron 8SE, 6SE plus Antares focal reducer
Celestron SE Goto
Kson 1026 ED (Carbon Fibre)
Skywatcher Synscan AZ Goto
Various EPs (BST, Televue, TMB, Xcel-LX)


#15
Donkeiller

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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,

Celestron 8SE, 6SE plus Antares focal reducer
Celestron SE Goto
Kson 1026 ED (Carbon Fibre)
Skywatcher Synscan AZ Goto
Various EPs (BST, Televue, TMB, Xcel-LX)


#16
AndyH

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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.
Tal 200K, Tal 2M, Tal 1, Tal M, Tal Alcor, Burgess CaF2/La 90mm Doublet Apo, Carton 60mm F16.7 Achro, PZO T50x70 Maksutov, Dark Star 6.25" F7.7 Newt/Dob
Eyepieces, mounts n stuff

Albums - http://stargazerslou...user/381-andyh/

#17
AndyH

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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.

Edited by AndyH, 28 December 2011 - 07:50 PM.

Tal 200K, Tal 2M, Tal 1, Tal M, Tal Alcor, Burgess CaF2/La 90mm Doublet Apo, Carton 60mm F16.7 Achro, PZO T50x70 Maksutov, Dark Star 6.25" F7.7 Newt/Dob
Eyepieces, mounts n stuff

Albums - http://stargazerslou...user/381-andyh/

#18
Donkeiller

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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?

Celestron 8SE, 6SE plus Antares focal reducer
Celestron SE Goto
Kson 1026 ED (Carbon Fibre)
Skywatcher Synscan AZ Goto
Various EPs (BST, Televue, TMB, Xcel-LX)





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