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1.25" eyepieces in a 76mm RAO?

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17 replies to this topic

#1 mpsteidle

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Posted 28 October 2020 - 11:38 AM

Hello.  I have a 76mm RAO that I would like to use 1.25" eyepieces with, but I do not wish to use a .965 to 1.25 adapter.  Does anyone make anything that would convert the drawtube to accept 1.25"?



#2 Pete W

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Posted 28 October 2020 - 11:58 AM

Here's an entire thread on this topic:

 

https://www.cloudyni...sic-refractors/

 

You should be able to find some do-able options here.  Good luck!

 

Pete


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#3 Garyth64

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Posted 28 October 2020 - 01:04 PM

There is also a thread on another way:  ( I will look for it.)

 

The idea is to replace the long 1-1/4" draw tube with a 1-1/4" chrome drain pipe from a hardware store.  Then a 3" section of aluminum tube, with a 1-1/4" ID, is slipped onto the 1-1/4" drain pipe.  Depending on the tube with the 1-1/4" ID, it may fit on easily, or may have to be persuaded into place.

I use a piece of brass, because it is what I had, and it worked very nicely.  The brass is heavier than the aluminum, but the drawtube didn't have any slop.

 

Here's my sears 6339a:

 

1.25 sleeve.jpg

 

I did a similar thing on my 10TE:

 

tubes 2.jpg


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#4 Pete W

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Posted 28 October 2020 - 02:55 PM

Here's another link that covers converting the pull tube to 1.25"

 

https://www.cloudyni...d-their-clones/

 

And here's one where the pull tube is replaced with a chrome pipe:

 

https://www.cloudyni...e-modification/

 

 

This second one is for a Towa scope, not a RAO so I'm not sure if it will work for yours.

 


Edited by Pete W, 28 October 2020 - 03:05 PM.

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#5 Garyth64

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Posted 28 October 2020 - 03:34 PM

Thanks Pete, that first link is the one I was going to look for.



#6 mpsteidle

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Posted 28 October 2020 - 09:23 PM

Here's an entire thread on this topic:

 

https://www.cloudyni...sic-refractors/

 

You should be able to find some do-able options here.  Good luck!

 

Pete

The problem is I have a scope with the pull-out tube, and I don't think most of those solutions will work with it.  I believe most of those use the ~36mm thread, which is much larger than the pull out tubes.  I would really like to just have a replacement barrel I could thread into the end of the tube, though that is seeing much less likely to be readily available.  Perhaps I just need to machine one.



#7 Garyth64

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Posted 28 October 2020 - 09:27 PM

What brand scope do you have?  If it is a Sears or Tasco, even some others, and you have a long pull out draw tube, the "fix" has been shown in the links.

 

Pictures will really help.


Edited by Garyth64, 28 October 2020 - 09:27 PM.


#8 mpsteidle

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Posted 28 October 2020 - 09:57 PM

The scope is an ATCO, pictures below.  The thread diameter is ~30mm.

 

https://imgur.com/a/LgWfU7X


Edited by mpsteidle, 28 October 2020 - 09:59 PM.


#9 Garyth64

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Posted 29 October 2020 - 07:59 AM

Yes, in one of the links, Chuck shows a focuser that is different from yours and mine.  He uses different threaded rings to finally get to the VB.  You/we cannot do that.  You have to look in the other link, below.

 

Your ATCO looks identical to a Tasco 10TE:

 

10TE rebuilt box 1.jpg

 

So with that, there are some things you can do, as mentioned before.

You can add a 1-1/4" ID sleeve over your 1-1/4" draw tube.

 

https://www.cloudyni...clones/?hl=10te

 

Or you can buy a .965" to 1-1/4" VB.

 

Or you can put a different sleeve, like the brass one of mine shown in #3, or even do something like this:

 

old and new.jpg

 

In that one, I had a piece of tube, that was 1-1/2" in diameter that was threaded on the inside for a 1-1/4" VB.  I purchase a 1-1/4" drain pipe and cut it down to 9".  You just have to fill in the gap between the two diameters so you have a very tight fit.  I used the soft half of self adhesive Velcro.

 

One more idea, but this one eliminates the long draw tube.  The long draw tube is taken out leaving only the shorter tube of the focuser.  You will notice that there is a black ring that is screwed into that tube.  A 1-1/4" VB will screw into that tube, but it is way too short for you to focus anything.  I added in an extension from a long barlow that I had.  

 

focuser compare.jpg

 

You can see the different lengths of each.  I believe I was able to use the focuser with the extension tube straight thru without a diagonal.


Edited by Garyth64, 29 October 2020 - 08:16 AM.


#10 mpsteidle

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Posted 29 October 2020 - 08:21 AM

I believe I will try extending the larger tube, and eliminate the skinny one. You've been tremendously helpful, thank you!
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#11 Pete W

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Posted 29 October 2020 - 05:28 PM

I've used different methods to adapt my RAO Sears 6339a and Tasco 10TE scopes for 1.25" eyepieces.  On the Tasco (white tube) I removed the inner pull tube and used the Vixen 36.4mm visual back with two thread-on extenders and one slip-in extender.   For the Sears (gray tube) I kept the pull tube and threaded on a 30mm to 42mm (T thread) setup ring along with a male T thread  1.25" visual back - see the close up.

 

20201029_170618.jpg    post-40313-0-52377100-1598380188.jpg

 

I generally favor the Sears 6339a setup, but the step-up ring solution on the Sears is only secure with lightweight eyepieces (orthos, plossls, konigs).  I wouldn't trust the minimal threads of the step-up ring to hold a heavy Nagler or similar sized eyepieces.   I've been lucky to have two thread-on extenders I can use on the Tasco, but without these I needed three slip-in tube extenders which was too much - it seemed less secure.   


Edited by Pete W, 29 October 2020 - 05:32 PM.

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#12 mpsteidle

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Posted 29 October 2020 - 07:16 PM

I wasn't happy with any of these solutions so I just machined my own adapter.  

 

iRCTlK2.jpg

 

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#13 mpsteidle

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Posted 29 October 2020 - 07:18 PM

If anyone wishes to make their own, the thread turned out to be roughly 30mm x 0.7


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#14 Pete W

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Posted 29 October 2020 - 07:30 PM

That is so cool!   Be careful...you may get requests from folks on this forum for a few of these! grin.gif  


Edited by Pete W, 29 October 2020 - 07:37 PM.

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#15 mpsteidle

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Posted 29 October 2020 - 07:30 PM

That is so cool!   Be careful...you may get requests from folks on this forums for a few of these! grin.gif  

I would be happy to make them if people are happy to pay.  It certainly turned out nicely!


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#16 Garyth64

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Posted 29 October 2020 - 07:33 PM

It looks great!  PM sent a few minutes ago.  Yes! Come up with a price.



#17 Defenderslideguitar

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Posted 29 October 2020 - 07:39 PM

My Tasco 10 te  1958   somehow nicely fit the Vixen 1.25 screw on visual back    i took off my Mayflower 814  where I had been using 1.25 eyepieces.........So I ordered another one to go on the Mayflower. I ordered it in August     coming very slowly from Japan     I was warned that it could take until November but I thought what the heck    November will get here is all due time and I am expecting it in a week or so

 

Agree that it is so nice to be able to switch back and forth from .965 to 1.25


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#18 BlueTrane2028

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Posted 29 October 2020 - 07:40 PM

I have an old department store refractor from my youth.  I bought a diagonal that's .965 coming in and 1.25 going out.  Solved the issue.


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