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Clicklock, thumbscrews, or compression ring which is most secure?

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#1 T~Stew

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Posted 13 February 2024 - 12:43 AM

I need to extend the drawtube of my Skywatcher Quattro. After determining its an odd size, the choices are very limited but there are a few. TS sells an appropriate extension. I could then put the stock 2-thumbscrew ring back on. Those have already scratched up my CC just in my few tests so far. I could also replace the 2 screw ring with a TS-Optics 2" Adapter with Compression Ring (out of stock though), or just use a Baader 2" ClickLock clamp and not need any extension (it already adds enough). The Baader would probably be my choice, could get it without having to go overseas, but are they as accurate for a fast imaging newtonian?


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#2 Skywatchr

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Posted 13 February 2024 - 02:44 PM

I need to extend the drawtube of my Skywatcher Quattro. After determining its an odd size, the choices are very limited but there are a few. TS sells an appropriate extension. I could then put the stock 2-thumbscrew ring back on. Those have already scratched up my CC just in my few tests so far. I could also replace the 2 screw ring with a TS-Optics 2" Adapter with Compression Ring (out of stock though), or just use a Baader 2" ClickLock clamp and not need any extension (it already adds enough). The Baader would probably be my choice, could get it without having to go overseas, but are they as accurate for a fast imaging newtonian?

If you look at the "demo" video on the Baader website, and look closely, you will still see some wobble.  But as the guy keeps saying "it won't turn" which isn't the same as sag or wobble.

 

It just seems too "short" to provide much lateral stability to me.

 

https://www.baader-p...ece-clamps.html


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#3 CowTipton

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Posted 13 February 2024 - 02:59 PM

I replaced my stock Sky watcher 2-thumbscrew ring with this Baader:

https://agenaastro.c...an-2956254.html

 

The original screws off and this Baader screws right on.

 

Just some numbers for you:

The original SW ring adds 12mm to the end of the drawtube.

The Baader clicklock adds 30mm.

 

I find it very stable, much much better than the original SW 2-thumbscrew.  My sag and tilt issues seem to be well-corrected after the switch.

 

I use it with both the Starizona Nexus at f/3.45

get.jpg?insecure

 

and with the Paracorr2 at f/5.29

get.jpg?insecure

 

In my case it's not the Quattro but the 14" goto dobsonian and I shoot very short subs with my DSLR for now.

But I believe they use the same focuser so hopefully it will work for you as well.


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#4 T~Stew

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Posted 13 February 2024 - 05:50 PM

Another random thought... instead of using an actual extension of some sort, since options are limited, would it work as well just to use a bushing to make up the gap between the drawtube clamp ring and the flange of the coma corrector? It'd probably have to be custom, and I am trying to get my hands on a lathe. 

 

If you look at the "demo" video on the Baader website, and look closely, you will still see some wobble.  But as the guy keeps saying "it won't turn" which isn't the same as sag or wobble.

 

It just seems too "short" to provide much lateral stability to me.

 

https://www.baader-p...ece-clamps.html

Hmm that could be problematic. The stock clamp has the same inside diameter as the drawtube, so I guess the two screws push it against the drawtube down the full length of the CC. Would the Clicklock then center it so it doesn't touch drawtube at all, and its just supported ~30mm laterally?

 

If I got the extension instead of the clicklock, would a compression clamp work as well as the stock thumbscrew one (just to prevent the screws from marring a $500 corrector) like this one if its ever available again https://www.teleskop...newtonians-4018

 

Or perhaps just replacing the stock thumbscrews with nylon tipped ones if I can find them?

 

 

 

 

I replaced my stock Sky watcher 2-thumbscrew ring with this Baader:

https://agenaastro.c...an-2956254.html

 

The original screws off and this Baader screws right on.

 

Just some numbers for you:

The original SW ring adds 12mm to the end of the drawtube.

The Baader clicklock adds 30mm.

 

I find it very stable, much much better than the original SW 2-thumbscrew.  My sag and tilt issues seem to be well-corrected after the switch.

 

I use it with both the Starizona Nexus at f/3.45

 

 

and with the Paracorr2 at f/5.29

 

 

In my case it's not the Quattro but the 14" goto dobsonian and I shoot very short subs with my DSLR for now.

But I believe they use the same focuser so hopefully it will work for you as well.

Yeah I need about 20mm of extension but I think 18 is sufficient. Good to hear yours is working well. Its tough to tell in your pics, especially the Paracorr one as the stars seem to not be sharp and perhaps some coma...

 

Its curious you could use both correctors? For my Quattro the focuser does not have enough travel for both (reason I need the extension). When I use the Nexus the focuser is bottomed out right around the focal point. Barely usable like that. But add the P2 and not only do I extend the focuser all the way out, but it needs to go further yet to reach focus. Maybe its a different focuser with more range or your higher f/ratio compresses the focal shift (I'm not really sure how that all works)? 



#5 Skywatchr

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Posted 13 February 2024 - 07:33 PM

The problem with Nylon (or other plastic tipped) screws, is they "mush". They're not as solid as metal screws.  Plus the "tip" is not going to allow for fully being threaded into the visual back which could strip the threads quite easily.

As far as "shimming" the Paracorr for "super fit", it would be hard to get the right thickness which would be very thin.  But if you could find the right shim material, you could adhere 3 equally spaced "pads" toward the front to make sure the nose stays centered, and the Baader clicklock will center the other end. There must be some "clearance" in eyepiece holders/visual backs so nothing binds up inserting, or pulling out.  How much clearance can vary from machining tolerances.

Another alternative is a bit more extreme.  That would be to drill and tap 3 equally spaced holes for short grub screws in the drawtube to precisely center the nose of the Paracorr.  But then, it's still screws to mar the Paracorr.  It would be rock solid though. grin.gif

 

Unfortunately it appears the threads on your drawtube are M54.3x1. (according to your link)  Not M54x0.75 which is more "common" (so to speak).  So be sure the Baader will fit because I might be the wrong thread pitch.

 

(Under the technical data)

Telescope side thread: M54,3x1 male (fits directly to the Skywatcher focusers)



#6 T~Stew

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Posted 14 February 2024 - 12:30 PM

Gotcha. Going from all threaded connections in all my other imaging rigs to these is a big step backwards. 

 

I think the clicklock with 3 shims would be a little tricky, and risk them falling out if not totally perfect. Just the 2 clamp screws and 2 shims would be easier, and keep everything justified to one side of the drawtube. So that brings me back to ordering the expensive extension. 

 

Yes the threads are M54.3 x1 which is why there are so few options. The Baader clicklock is specifically for Skywatcher M54x1 so I assume they got it right or close enough. The only other options I found are the TS-optics pieces which I assume are custom made for them, I don't see anything like them available eslewhere. 


Edited by T~Stew, 14 February 2024 - 12:34 PM.


#7 Dan_I

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Posted 14 February 2024 - 04:18 PM

Gotcha. Going from all threaded connections in all my other imaging rigs to these is a big step backwards. 

 

I think the clicklock with 3 shims would be a little tricky, and risk them falling out if not totally perfect. Just the 2 clamp screws and 2 shims would be easier, and keep everything justified to one side of the drawtube. So that brings me back to ordering the expensive extension. 

 

Yes the threads are M54.3 x1 which is why there are so few options. The Baader clicklock is specifically for Skywatcher M54x1 so I assume they got it right or close enough. The only other options I found are the TS-optics pieces which I assume are custom made for them, I don't see anything like them available eslewhere. 

It shouldn't be difficult to have a custom adapter machined from the focuser m54x1 thread to the Paracorr 2.4" thread of the right length? Perhaps it is listed already in Preciseparts options?



#8 T~Stew

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Posted 15 February 2024 - 12:26 AM

It shouldn't be difficult to have a custom adapter machined from the focuser m54x1 thread to the Paracorr 2.4" thread of the right length? Perhaps it is listed already in Preciseparts options?

I hadn't heard of them before. 

But how would it be possible? You can't really use the front threads of the Paracorr, and the rear threads are already used by the TV-IS adapter to the EFW/camera train. There aren't any more threads to use. 

Thinking about it, might be possible if its a 3-way adapter, adapting to the Skywatcher drawtube on one end, Paracorr on the inside of the other end, and outer threads to go to another adapter to bring back down to M54 in place of the TV-IS adapter. Hmm, sounds like a good project for when I get the lathe...



#9 Dan_I

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Posted 15 February 2024 - 04:56 AM

I hadn't heard of them before. 

But how would it be possible? You can't really use the front threads of the Paracorr, and the rear threads are already used by the TV-IS adapter to the EFW/camera train. There aren't any more threads to use. 

Thinking about it, might be possible if its a 3-way adapter, adapting to the Skywatcher drawtube on one end, Paracorr on the inside of the other end, and outer threads to go to another adapter to bring back down to M54 in place of the TV-IS adapter. Hmm, sounds like a good project for when I get the lathe...

 

If you find an extension with M54x1 male threads on one end and M68x1 female threads on the other end, this would do the job:

 

https://www.teleskop...orr-to-m68-5014



#10 T~Stew

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Posted 15 February 2024 - 02:44 PM

If you find an extension with M54x1 male threads on one end and M68x1 female threads on the other end, this would do the job:

 

https://www.teleskop...orr-to-m68-5014

Yes something like that could be made to work in theory... its like the 3-way adapter I was thinking about in my last post but this one obviously isn't designed for the Skywatcher focuser, so two other adapters would still be needed. One to adapt the Skywatcher drawtube threads to a common size,  and then one to adapt that to M68 male (since no M54x1-M68 adapter exists that I am aware), and provide the right extension or an extra extension piece in there somewhere.

But then we run into the stumbling block, no Skywatcher or even generic 54x1 threaded adapter I see go to any common size and still provide the proper bore for the Paracorr. TS sells the Skywatcher to T2 adapter but that won't work with the Paracorr obviously. 

This still seems like its only possible custom. Back to wanting to get that lathe...




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