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TAK FSQ106 Focusers

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#1 Lead_Weight

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Posted 19 May 2020 - 07:06 PM

I'm thinking about selling two of my scopes to pick up an FSQ106. I had thought about the NightCrawler but not sure I want to drop a few grand more after getting the scope. So I'm looking for some more economical focusers. There are lots of aftermarket focusers that attach to the existing manual focuser like the Pegasus Astro, the ZWO option, and I'm sure there are others. 

 

What has everyone had good luck with?



#2 ChrisWhite

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Posted 19 May 2020 - 07:12 PM

I was very close to buying an FSQ106 this spring.  The pandemic pushed me to take a more... price conscious route, but I did research the heck out of the focuser.  What I learned is that the design of the Tak focuser does not work very well with motor add-ons that replace the focus knobs.  I spoke to a lot of people who gave up out of frustration and just put on the NC. Like you, I didn't want to drop that kind of coin on the focuser, so Tolga helped me and recommended the Optec Leo.  It has a built in drawtube that racks in and out, so the focuser assembly of the Tak stays locked down.  It's a little bit more of a pain for rotation as you need to loosen a few grub screws IIRC.  I can't recall if the Tak rotator stays on or off... someone else will need to comment. 

 

But I would take a hard look at the LEO and be cautious about the replacement knob focusers. 

 

PS-  Jeff at Optec told me at the time he would be open to designing a direct drive focuser.  Might ask him about that. 


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#3 Lead_Weight

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Posted 19 May 2020 - 08:56 PM

Hmm, well, that's a bummer. I'm only considering it since I just picked up a ZWO6200 with filters and can't use it on two of my scopes since they don't support full frame. I thought I would trade both in, along with my ASI1600 camera to make up some of the difference. 



#4 sydney

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Posted 19 May 2020 - 09:14 PM

I really like the focuser on my FSQ106 ED.  It is just as good as the Feathertouch on my AP Stowaway and much better than the focuser on the TeleVue NP101is that I had.

 

However, for imaging I already owned an Optec TCF focuser, so purchased the adapter to attach it to the FSQ.  It attaches  directly to the stock focuser so there is no need for any modifications, and I still use the “captain’s wheel” rotator for framing images. The Optec TCF is an excellent and reliable focuser.  I believe some folks have also had good results with the Robofocus on their Taks. 

 

I agree that Tolga is excellent and knowledgeable resource.

 

https://www.tolgaastro.com/

https://www.optecinc...g/tcf/17670.htm

http://www.robofocus.com/products.htm



#5 leviathan

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Posted 20 May 2020 - 04:12 AM

I've ordered ZWO EAF for my FSQ-106 stock focuser. Will post once I get and test it.

But in general I like Tak focuser, it can handle modern light cameras and filter wheels quite well. It was a times of old heavy imaging rigs going as heavy as 10kg in case of something like FLI 16803 and FW that stock focuser obviously coulnd't handle. Nowadays with everything attached you barely exceed 2kg.



#6 Lead_Weight

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Posted 20 May 2020 - 08:39 AM

I've ordered ZWO EAF for my FSQ-106 stock focuser. Will post once I get and test it.

But in general I like Tak focuser, it can handle modern light cameras and filter wheels quite well. It was a times of old heavy imaging rigs going as heavy as 10kg in case of something like FLI 16803 and FW that stock focuser obviously coulnd't handle. Nowadays with everything attached you barely exceed 2kg.

That's about what I estimate for the 2" filter wheel, camera and OAG. I've heard mixed things on the ZWO. Some have a lot of slop. Maybe it's inherent with this type of focuser, not sure. But my moonlites are pretty solid. I guess there's also Pegasus focus box, as well as PrimaLuce who have both the bolt on, as well as a replacement for the focuser.



#7 HunterofPhotons

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Posted 20 May 2020 - 12:51 PM

Hi Andrew,

You didn't say which FSQ106 model you were interested in and that may make a difference.

The older 106N was pretty robust and I don't remember people having focuser problems of any significance.

The newer one spawned some complaints but people started hanging considerable weight on them.

I imaged for many years with an older 106N with a RoboFocus but I made sure it was properly and securely fastened with a strong bracket.

The proper settings for the RoboFocus were important, too.

 

Jenkins bracket,sm.jpg

 

dan k.



#8 Lead_Weight

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Posted 20 May 2020 - 01:26 PM

I would be picking up the newer EDX4.



#9 mfarrell

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Posted 23 May 2020 - 03:19 PM

I have an early version of the FSQ-106ED and I've tried a couple different focuser options, both of which are serviceable but neither are ideal:

 

Starizona Microtouch.  I already had the old Microtouch controller so I picked up the motor for ~$250 if I recall.  With the older controller, the resolution was 10 micron per step, which is quite poor IMO for a f/5 scope.  The Microtouch attaches to the fine focus wheel via a gear that you install.  The motor housing clamps onto the fine focus assembly, so no brackets required which is nice.  While it did work reasonably well, I went away from this approach for a couple of reasons:

  • My Tak fine focuser had some slippage when pulling against gravity, which eventually adds up.  I doubt it has that much real effect on autofocus accuracy but I prefer my focusing to be more precise and repeatable.  After I removed it, I was able to tighten up on the fine focus assembly nut which I think would have reduced but not quite eliminated the slippage.
  • The 10 micron per step resolution as mentioned before.
  • I was not a big fan of having a separate control box that I have to mount on the scope and run a wire over to the motor.  That's one of the nice features of the ZWO EAF and the Sesto Senso for example.  
  • I measured backlash of ~50 microns which I partly attributed to having the extra gear between the motor and the fine focus shaft.  

ZWO EAF.  I got this thinking that since the motor would be connected directly to the pinion shaft, I could eliminate the slippage and drift over time and hopefully improve the backlash.  I was half right:

  • Step size was 3-3.5 microns which I believe is fine for f/5, and probably even if using a reducer.  I know some manufacturers tout having 1 micron or sub-micron resolution but I don't think it's really necessary.
  • It is true that there is no more slip with the EAF, however it's not quite that simple.  The flexible coupling provided by ZWO with the EAF is great for dealing with misalignment between the motor shaft and the pinion shaft, but it has very poor torsional stiffness.  This means that the motor has to "wind up" the coupling which acts like a spring before the focuser will actually move.  This imparts a kind of backlash and very poor reproducibility and fine movement.  I found a cheap coupling on Amazon that has a split-ring clamp design which avoids some of the set screw issues with a truly solid coupling design, yet it still has excellent torsional stiffness and transmits the motor torque with essentially no spring effect.  This is a must-upgrade feature IMHO.
  • I had no issues with the ZWO bracket for Tak focusers, although it's not quite as clean looking as the fully intregrated clamp housing design of Microtouch and Sesto Senso.
  • And then the backlash.  Oh boy is there a lot of backlash, in the ballpark of 250 microns if I remember correctly, or something like 75-80 steps.  This is even after upgrading the coupling, which means that essentially all of this comes from the internal gearbox used to convert the stepper motor output into something that has decent resolution for the coarse focus knob.  The good news is that it is pretty repeatable, and the backlash compensation in the driver works well.  Since I set up my autofocus to approach from the same direction each time, it's not a big deal.

In terms of the Tak focuser itself, I'm not a huge fan but I haven't forked over the big bucks to upgrade it to a NightCrawler or FeatherTouch 3515.  I did stiffen it up as much as reasonable by tightening the teflon pads on the underside of the drawtube.  As a side note even top of the line focusers like FeatherTouch have to be "tuned" differently for visual vs imaging.  In order to get a nice "feel" with the Tak focuser it ends up too droopy for imaging.  Tighten it up for less droop and now it doesn't feel buttery smooth if focusing by hand.  The 3.5" FeatherTouch is able to get much closer to an ideal balance but there is still a trade-off.  Such is life or at least my experience.  I also minimize how much the tube is racked out to just a few millimeters for the FSQ.  And, I added a Guide scope ring that supports my adapters near the camera and bolts to the scope dovetail.  Since the autofocuser has to be able to move the drawtube, the guide scope ring screws aren't very tight, but I do believe it offers some additional support when not pointing straight up.  If you're using an OAG then that's probably not necessary and the guiding can accommodate for any drawtube sag.

 

Hope this helps.  It would sure be nice to have a NightCrawler which I'm sure will make the focuser just "disappear" and work without having to think about it, but personally I have so far been unable to justify the expense.  

-Matthew


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#10 Lead_Weight

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Posted 23 May 2020 - 06:23 PM

Matthew, thanks for the insight, this was very helpful. Has anything changed with the focuser with the EDX4?

#11 mfarrell

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Posted 23 May 2020 - 07:10 PM

Matthew, thanks for the insight, this was very helpful. Has anything changed with the focuser with the EDX4?

Sorry, but I don't know too much about the focuser changes up to the EDX4 (pretty sure the optics are identical).  At some point they got rid of the "capstan's wheel" which allows rotation and possibly some misalignment.  The focuser itself looks the same to me but I can't be sure what's inside.  Some people seem to love it, while others hate it.



#12 leviathan

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Posted 24 May 2020 - 04:02 AM

Hi Matthew, that was really helpful ! My EAF is lost somewhere in coronavirus madness. foreheadslap.gifHopefully I can test it on EDX-III focuser once it arrives.

 

Can you also share whether you locked the stock focuser while using EAF or left it unlocked ?


Edited by leviathan, 24 May 2020 - 04:05 AM.


#13 mfarrell

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Posted 25 May 2020 - 03:32 PM

Hi Matthew, that was really helpful ! My EAF is lost somewhere in coronavirus madness. foreheadslap.gifHopefully I can test it on EDX-III focuser once it arrives.

 

Can you also share whether you locked the stock focuser while using EAF or left it unlocked ?

If you mean the lock lever underneath the FSQ focuser, I left that unlocked otherwise the EAF would not be able to rack the focuser in and out.  



#14 Lead_Weight

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Posted 25 May 2020 - 06:10 PM

Just saw this YouTube video today with someone who used a PrimaLuce Labs focuser. https://m.youtube.co...e&v=NHg5Mgl1l7I

#15 Ken82

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Posted 25 May 2020 - 07:55 PM

Fit a senso sesto v2 perfect ! 
 

my focuser was slipping quite badly before fitting but works perfect now. 
 

Attached Thumbnails

  • 80DB46B9-B886-4674-97CC-F3F22B397625.jpeg

Edited by Ken82, 25 May 2020 - 07:59 PM.

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#16 Lead_Weight

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Posted 25 May 2020 - 08:36 PM

Fit a senso sesto v2 perfect ! 
 

my focuser was slipping quite badly before fitting but works perfect now. 
 

Did you have to get any special adapters, or did it work out of the box as is?



#17 Ken82

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Posted 25 May 2020 - 08:41 PM

Out of the box. All adapters are included for different scopes .
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#18 ChrisMoses

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Posted 26 May 2020 - 08:44 PM

Hi

I had Tolga install a Nightcrawler for me before he even shipped it out. It was a great decision.  It just screws on and works.

Expensive, but well worth it!  They are incredible focusers


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