Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Unitron 114 Visual Back

  • Please log in to reply
21 replies to this topic

#1 William Whitaker

William Whitaker

    Vostok 1

  • -----
  • topic starter
  • Posts: 120
  • Joined: 07 Jul 2011
  • Loc: NE Tennessee

Posted 22 July 2021 - 08:14 PM

Following the advice of some members here, I ordered a 1.25" visual back from ScopeStuff for my 114.

Disappointingly, it doesn't fit my scope.  It only fits 1/2 turn, so can't even a fudge it! Further, measuring the major diameters of the male thread shows that the original VB is 1.385" while the one from SS measures 1.398". That's oversize by .013", which is a LOT!

I spoke at length with Jim at SS and will be returning the VB tomorrow.

He suggested perhaps boring out the original .925 VB (which fits perfectly...) to 1.25. And at first I thought that might be a possibility. But, confirming the dimensions, there is just not enough "meat" in the old VB. NO WAY.

 

We confirmed my initial measurement following the technique that SS recommends and couldn't find an error.

I asked about a simple exchange and was told that all pieces in stock are the same to within .003". They use precision go/no-go gauges for QC. That's good. But how can a piece that's apparently over-size slip through??

I'm at a loss. Does anyone here know of another vendor who sells replacement visual backs in 1.25" for the Unitron 114? One that fits....?

This isn't rocket science! Right?!

 

Any and all suggestions welcome!

 

Thanks

~W



#2 Terra Nova

Terra Nova

    ISS

  • *****
  • Posts: 25,781
  • Joined: 29 May 2012
  • Loc: 39.07°N, 229m AMSL, USA

Posted 22 July 2021 - 08:38 PM

Try Tony C’s adapters at Astronomy Shoppe.


  • rweisberg, William Whitaker and Bomber Bob like this

#3 William Whitaker

William Whitaker

    Vostok 1

  • -----
  • topic starter
  • Posts: 120
  • Joined: 07 Jul 2011
  • Loc: NE Tennessee

Posted 22 July 2021 - 10:34 PM

Terra N.~

Not seeing anything there. Can you be specific?

Thanks,

W



#4 Kasmos

Kasmos

    Skylab

  • *****
  • Posts: 4,236
  • Joined: 19 Aug 2015
  • Loc: So Cal

Posted 23 July 2021 - 12:33 AM

Following the advice of some members here, I ordered a 1.25" visual back from ScopeStuff for my 114.

Disappointingly, it doesn't fit my scope.  It only fits 1/2 turn, so can't even a fudge it! Further, measuring the major diameters of the male thread shows that the original VB is 1.385" while the one from SS measures 1.398". That's oversize by .013", which is a LOT!

I spoke at length with Jim at SS and will be returning the VB tomorrow.

He suggested perhaps boring out the original .925 VB (which fits perfectly...) to 1.25. And at first I thought that might be a possibility. But, confirming the dimensions, there is just not enough "meat" in the old VB. NO WAY.

 

We confirmed my initial measurement following the technique that SS recommends and couldn't find an error.

I asked about a simple exchange and was told that all pieces in stock are the same to within .003". They use precision go/no-go gauges for QC. That's good. But how can a piece that's apparently over-size slip through??

I'm at a loss. Does anyone here know of another vendor who sells replacement visual backs in 1.25" for the Unitron 114? One that fits....?

This isn't rocket science! Right?!

 

Any and all suggestions welcome!

 

Thanks

~W

You might already have one and could try this:

 

https://www.cloudyni...ors/?p=10473440


  • William Whitaker likes this

#5 Terra Nova

Terra Nova

    ISS

  • *****
  • Posts: 25,781
  • Joined: 29 May 2012
  • Loc: 39.07°N, 229m AMSL, USA

Posted 23 July 2021 - 07:44 AM

Terra N.~

Not seeing anything there. Can you be specific?

Thanks,

W

It looks like he has discontinued them. They were custom CNC made and worked very well. You might also try CN member Xavier who also did a custom run of them.


  • William Whitaker likes this

#6 davidmcgo

davidmcgo

    Soyuz

  • *****
  • Posts: 3,710
  • Joined: 09 Oct 2004
  • Loc: San Diego, CA

Posted 23 July 2021 - 08:17 AM

I think there was variation between Unitrons.  I had to use the smaller size Scope Stuff sold and it is a bit tight in mine.  The ones Tony had at Astronomy-Shoppe were nicer made but the threads did not fit my drawtube.

The backwards Meade 1.25” visual back screws in with some slop but consumes extra back focus.

 

 

Dave


Edited by davidmcgo, 23 July 2021 - 08:18 AM.


#7 dusty99

dusty99

    Viking 1

  • *****
  • Posts: 798
  • Joined: 13 Jun 2009

Posted 23 July 2021 - 08:53 AM

SOUNDS LIKE THIS ONE WON'T WORK WITH UNITRON.

 

 

 

 

I’m not convinced this is a real Vixen part, but it looks like the older ones:

 

https://www.ebay.com...rsAAOSwJ6NbwZyu

 

Maybe someone knows if this will fit a Unitron 60mm?  At present I’m using the friction-fit Blue Fireball .965 to 1.25 converter, but only use lighter eyepieces.  


Edited by dusty99, 23 July 2021 - 05:08 PM.

  • William Whitaker likes this

#8 William Whitaker

William Whitaker

    Vostok 1

  • -----
  • topic starter
  • Posts: 120
  • Joined: 07 Jul 2011
  • Loc: NE Tennessee

Posted 23 July 2021 - 08:53 AM

Thank you all. At least it appears that I have some options to try. But I can see that this is going to take some time. I had naively thought it would be simple plug 'n' play.

But Nooooo. Life doesn't work that way. There are always thorns and brambles in the path of least resistance!

So much for Occam's Razor!!


  • CltFlyboy likes this

#9 sdedalus83

sdedalus83

    Viking 1

  • *****
  • Posts: 838
  • Joined: 30 Oct 2016

Posted 23 July 2021 - 10:12 AM

But how can a piece that's apparently over-size slip through??

I'm at a loss. Does anyone here know of another vendor who sells replacement visual backs in 1.25" for the Unitron 114? One that fits....?

This isn't rocket science! Right?!

 

Any and all suggestions welcome!

 

Thanks

~W

The Scope Stuff adapters are 35.5mm - 1.398” - and 36.25mm - 1.427”. It sounds like yours was the right size, not oversized. As mentioned earlier, Unitrons had some variation over the years.

 

The Vixen adapter has a nominally larger thread diameter than either Scope Stuff adapter. I have noticed variation with them but not enough to seem likely that any would fit. There might be someone who could modify the Vixen to match the threads on your VB. I know Sheldon Faworski modifies standard 1.25” eyepiece barrels to fit Kowa spotting scope eyepiece threads.



#10 Terra Nova

Terra Nova

    ISS

  • *****
  • Posts: 25,781
  • Joined: 29 May 2012
  • Loc: 39.07°N, 229m AMSL, USA

Posted 23 July 2021 - 10:44 AM

I’m not convinced this is a real Vixen part, but it looks like the older ones:

 

https://www.ebay.com...rsAAOSwJ6NbwZyu

 

Maybe someone knows if this will fit a Unitron 60mm?  At present I’m using the friction-fit Blue Fireball .965 to 1.25 converter, but only use lighter eyepieces.  

The Vixen adapter and it’s clones does not fit Unitron drawtubes.


  • dusty99 and anonymonachos like this

#11 dusty99

dusty99

    Viking 1

  • *****
  • Posts: 798
  • Joined: 13 Jun 2009

Posted 23 July 2021 - 03:52 PM

Good to know, thanks.  
 

The Vixen adapter and it’s clones does not fit Unitron drawtubes.


  • Terra Nova and anonymonachos like this

#12 dusty99

dusty99

    Viking 1

  • *****
  • Posts: 798
  • Joined: 13 Jun 2009

Posted 23 July 2021 - 05:16 PM

This probably won't help the OP, but for the record, I tried the Celestron visual back on two different threaded Unitron draw tubes (one from a 62mm/900mm and one from a 60mm/700mm - both early vintage, I think) and the Celestron part didn't fit either, and both were different (one almost fit, and loosely threaded on, but was too big for the vis. back to snug down, the other was of a larger OD and the Celestron part just slipped inside).

 

 

 

You might already have one and could try this:

 

https://www.cloudyni...ors/?p=10473440



#13 Kasmos

Kasmos

    Skylab

  • *****
  • Posts: 4,236
  • Joined: 19 Aug 2015
  • Loc: So Cal

Posted 23 July 2021 - 11:12 PM

This probably won't help the OP, but for the record, I tried the Celestron visual back on two different threaded Unitron draw tubes (one from a 62mm/900mm and one from a 60mm/700mm - both early vintage, I think) and the Celestron part didn't fit either, and both were different (one almost fit, and loosely threaded on, but was too big for the vis. back to snug down, the other was of a larger OD and the Celestron part just slipped inside).

My Unitron 114 is a circa '57-'58 62mm and the Celestron VB is from '79. It's been said that over the years the Celestron VBs have slightly different threads so it might be partially be due to that.



#14 DreamWeaver

DreamWeaver

    Vanguard

  • *****
  • Posts: 2,151
  • Joined: 30 Dec 2008
  • Loc: Tucson, AZ

Posted 24 July 2021 - 12:14 AM

Was there a Japanese company that made them in the past?  An adapter was included in my circa mid ‘60’s 114, that also fits my circa ‘55-‘56 114.

 

In the image below, the adapter that fits my Unitron is on the left.  On the right, the Unitron adapter on top of the Vixen adapter. You can see the size difference of the threaded diameters.

Attached Thumbnails

  • 9AD3F667-489E-4FE6-88A4-098C1D60F75A.jpeg

Edited by DreamWeaver, 24 July 2021 - 01:19 AM.

  • Terra Nova likes this

#15 anonymonachos

anonymonachos

    Lift Off

  • *****
  • Posts: 3
  • Joined: 08 Jun 2021

Posted 26 July 2021 - 03:58 PM

I have the same exact problem.  the scopestuff VB does not fit, and I tried it on 114s from three different decades.  the other size that he sells, however, fits perfectly on a Lafayette and Monolux that I have.  I will take suggestions to heart.  It has been suggested that the visual back can be printed on a 3D printer, and of course there is the Celestron SCT option.  I also have an adapter, so I will have to try that for a while, I guess.  I am trying to keep everything together , so if the OTA did not come with EPs, I have decided to use 1.25s, unless I find the .965s to complete the kit.


Edited by anonymonachos, 26 July 2021 - 06:55 PM.


#16 William Whitaker

William Whitaker

    Vostok 1

  • -----
  • topic starter
  • Posts: 120
  • Joined: 07 Jul 2011
  • Loc: NE Tennessee

Posted 26 July 2021 - 09:35 PM

A friend of mine who has very good lathe skills is going to make one for me. He will have the drawtube and the old .965 VB to work with. So he'll be able to fit the parts and not just try to cut to a mythical specification.wink.png


  • DreamWeaver, Terra Nova, Bomber Bob and 1 other like this

#17 anonymonachos

anonymonachos

    Lift Off

  • *****
  • Posts: 3
  • Joined: 08 Jun 2021

Posted 27 July 2021 - 02:00 PM

Please let me know if he would be willing to make me some, and the cost if he is willing to do so.  I can use more than one set.


Edited by anonymonachos, 27 July 2021 - 02:01 PM.


#18 Bomber Bob

Bomber Bob

    ISS

  • *****
  • Posts: 20,346
  • Joined: 09 Jul 2013
  • Loc: The Swamp, LA (Lower Alabama)

Posted 27 July 2021 - 05:38 PM

A friend of mine who has very good lathe skills is going to make one for me. He will have the drawtube and the old .965 VB to work with. So he'll be able to fit the parts and not just try to cut to a mythical specification.wink.png

William, is that 1.38" thread FEMALE?  I found a Unitron .965" / 1.25" adapter in the shed:

 

Unitron - 965 and 125 Flip Tube Adapter T01.jpg

 

The male thread is 1.38" on my digital caliper.

 

You're welcome to it -- I don't have any Unitron gear.


  • DreamWeaver and William Whitaker like this

#19 rweisberg

rweisberg

    Explorer 1

  • *****
  • Posts: 79
  • Joined: 30 Dec 2009
  • Loc: Gold Canyon, Arizona

Posted 11 October 2021 - 08:06 PM

Try Tony C’s adapters at Astronomy Shoppe.

Thanks for the info. I ordered one for my Unitron 114.  The web site says these are "new" and the site is dated in 2021. I believe that they are making them still and I received a thank you notice after I paid with PayPal.

 

Here is the site: http://astronomy-sho...m/?page_id=1730

 

Randy


Edited by rweisberg, 11 October 2021 - 08:10 PM.

  • mdowns likes this

#20 Terra Nova

Terra Nova

    ISS

  • *****
  • Posts: 25,781
  • Joined: 29 May 2012
  • Loc: 39.07°N, 229m AMSL, USA

Posted 12 October 2021 - 09:25 AM

Thanks for the info. I ordered one for my Unitron 114.  The web site says these are "new" and the site is dated in 2021. I believe that they are making them still and I received a thank you notice after I paid with PayPal.

 

Here is the site: http://astronomy-sho...m/?page_id=1730

 

Randy

They work quite well. I have one myself. 


  • rweisberg likes this

#21 rweisberg

rweisberg

    Explorer 1

  • *****
  • Posts: 79
  • Joined: 30 Dec 2009
  • Loc: Gold Canyon, Arizona

Posted 12 October 2021 - 09:36 AM

They work quite well. I have one myself. 

Question: if you go to the site discussed for the adapter, one of the images shows two different sizes of draw tubes. Do older 114's have larger draw tubes? This may be the answer to my question of the unidentified optical part that came with my telescope. It looks like a barlow lens, but is too big to fit in my draw tube. Its diameter is about 1.5 inches.  Randy



#22 Terra Nova

Terra Nova

    ISS

  • *****
  • Posts: 25,781
  • Joined: 29 May 2012
  • Loc: 39.07°N, 229m AMSL, USA

Posted 12 October 2021 - 09:49 AM

All of the Unitron drawtubes I’ve had have been the same size and have been interchangeable on all my Unitrons. I do recommend having a second drawtube for the with the larger (1.25”) visual back. That way you aren’t having to unscrew the visual backs every time you want to change equipment.


  • rweisberg and anonymonachos like this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics