In praise of the 32mm TeleVue Plossil

[Moonshane]

The 32mm plossl and Panoptics elements come loose when you unscrew the nosepiece so be careful to start work over a soft clean surface.  The shorter ones have a field stop threaded ring.

[iPeace]

Sure enough, I unscrewed the barrel and it all came out in pieces.

Looking at the schematic, it looks like the top lense was upside-down...

Will clean, reassemble and report.

[FenlandPaul]

4 minutes ago, iPeace said:

Sure enough, I unscrewed the barrel and it all came out in pieces.

Looking at the schematic, it looks like the top lense was upside-down...

Will clean, reassemble and report.

Interesting read, Mike, and just replied to your PM.  If this doesn't correct it, let me know and you're welcome to return it. 

Paul

[iPeace]

1 minute ago, FenlandPaul said:

Interesting read, Mike, and just replied to your PM.  If this doesn't correct it, let me know and you're welcome to return it. 

Paul

Did a quick test before cleaning - having inverted the top lense, the edge focus issue has disappeared. Will confirm after nocturnal test when clouds dissipate.

Thanks Paul, you're a true gent, but you won't be getting this one back!

[Piero]

Pheeew!  Lucky you, Mike, that it opened up so easily!  

I will CERTAINLY NOT post ANY pics of my 20mm TV Plossl during / after its surgery..   

There'd be a serious chance for me to be banned from SGL forever due to serious criminal offence against an eyepiece!   

[Piero]

32 minutes ago, iPeace said:

Sure enough, I unscrewed the barrel and it all came out in pieces.

Looking at the schematic, it looks like the top lense was upside-down...

Will clean, reassemble and report.

 

So, let me understand in detail.   

The barrel screws at the bottom of the body via the retaining ring just above the barrel ring cut, right? 

.. and the lenses came out from the bottom, then? 

What is the black ring between the two lenses at the bottom of your photo?

 

If I am not wrong, this is the last version of 32mm Plossl (looking at the barrel type). 

[John]

The black ring will be a spacer I expect. The 2 elements in a plossl are separated by an air space maintained by the spacer. As I understand it, this gap varies depending on the focal length of the eyepiece and also on the focal length of the elements being used.

Many of the Tele Vue eyepieces that I've owned had a warning slip in the box not to unscrew the chrome barrel so they frequently use that method of keeping the optical element in place obviously.

 

[Piero]

Oh yes, the spacer, I forgot about that. That makes perfectly sense! Thanks John!

[iPeace]

13 minutes ago, Piero said:

 

So, let me understand in detail.   

The barrel screws at the bottom of the body via the retaining ring just above the barrel ring cut, right? 

.. and the lenses came out from the bottom, then? 

What is the black ring between the two lenses at the bottom of your photo?

 

If I am not wrong, this is the last version of 32mm Plossl (looking at the barrel type). 

Exactly as John said. Start with the chrome bit, then stack the front row of bits left to right, then the black bit slides down over the stack and screws onto the chrome bit.

Hope this is technical enough for all you readers out there...

[Piero]

1 minute ago, iPeace said:

Exactly as John said. Start with the chrome bit, then stack the front row of bits left to right, then the black bit slides down over the stack and screws onto the chrome bit.

Hope this is technical enough for all you readers out there...

Cheers Mate! 

You have made me curious to see a disassembled 20mm TV Plossl now! At least to see how it looks like! 

[iPeace]

Just now, Piero said:

Cheers Mate! 

You have made me curious to see a disassembled 20mm TV Plossl now! At least to see how it looks like! 

I'll get right on it.

[Piero]

3 minutes ago, iPeace said:

I'll get right on it.

Mine has a removable barrel but everything else is stuck in place. 

[iPeace]

1 minute ago, Piero said:

Mine has a removable barrel but everything else is stuck in place. 

Yes, I read your post(s) about that. Odd that there's such a difference.

[iPeace]

17 minutes ago, iPeace said:

I'll get right on it.

By the way, this was meant in jest.

I don't own a 20mm Plossl, but if I do at some point acquire one, I promise to disassemble it for your learning and entertainment.

[Highburymark]

43 minutes ago, iPeace said:

Exactly as John said. Start with the chrome bit, then stack the front row of bits left to right, then the black bit slides down over the stack and screws onto the chrome bit.

Hope this is technical enough for all you readers out there...

Obviously too technical for the bloke in the assembly plant who put it together.....

Slightly disproves the sometimes-heard claim that TV separately checks all EPs made in the Far East.

[iPeace]

8 minutes ago, Highburymark said:

Obviously too technical for the bloke in the assembly plant who put it together.....

Slightly disproves the sometimes-heard claim that TV separately checks all EPs made in the Far East.

Not too fast there, this one is pre-loved by more than one fellow observer; my own assumption is that it was disassembled at some point in time after it left TeleVue's care.

[John]

7 minutes ago, Highburymark said:

Slightly disproves the sometimes-heard claim that TV separately checks all EPs made in the Far East.

I suspect this one has been opened up since it was purchased new.

I think TV do check all the units in the USA before they go out for sale. This is taken from a report of a vist to Tele Vue's facility in 2007:

"...Little things like this made an impression on me as we walked through the plant.  But if I had to name one thing that really stood out, it would have to be their eyepiece testing room.  We've all heard, many times over the years that Tele Vue quality control tests every eyepiece.  Take note, this is not a statistically significant sample, but every single eyepiece.  Every one.  None the less, when we walked in the room and saw Ray with thousands of eyepieces stacked up behind him for testing, I was shocked.   I guess I'd never really grasped what that meant...."

 

[Highburymark]

Fair enough chaps. Happy to withdraw my sweeping inaccuracy.

[iPeace]

38 minutes ago, Highburymark said:

Fair enough chaps. Happy to withdraw my sweeping inaccuracy.

I feel that the skepticism which you voiced is all too valid in today's world and expect that it's shared by many others. It's good to have it addressed here among kindred souls.

Indeed, had the eyepiece not so easily separated into its component parts on the table before me, I would have most likely been thinking along similar lines.

As it is, this has been a very cool learning experience for me. I wouldn't go so far as to recommend to everyone to disassemble at least one green-lettered product in one's lifetime, but it's reassuring and instills confidence in one's ability to get stuff sorted, especially with the benefit of others' knowledge and experience.

My thanks again to all.

[John]

You could have also phoned Tele Vue and talked to someone about sorting out your issue. I spoke with David Nagler when I phoned a few of years back. He was very helpful indeed despite me being probably the 3rd owner of the product concerned.

 

 

[Stu]

Televue are excellent but not totally infallible. Once bought a new 3.7mm EthosSX and when it arrived the exit lens had a horrible frosted/crackled effect over about 50% of the area. It was replaced very quickly but had obviously sneaked past their QA. You don't often hear of examples like that though so they do seem very good.

[Pig]

100% manual  inspection from a quality perspective is very unreliable and issues will get through. Humans are simply not very good at 100% unless it is for very short time periods or low volumes, even then we get bored or complacent. As long as the retailer takes care of you and puts everything right I find most of us will be ok with it.  

I find the eye placement a little awkward at times with the TV 32mm, other than that it is a lovely eyepiece.

[iPeace]

24 minutes ago, Pig said:

I find the eye placement a little awkward at times with the TV 32mm, other than that it is a lovely eyepiece.

I agree. Now that all the glass in mine is pointing in the right direction, I am considering getting an eyeguard extender for it.

[Stu]

19 minutes ago, iPeace said:

I agree. Now that all the glass in mine is pointing in the right direction, I am considering getting an eyeguard extender for it.

Well worth it, they make a big difference to the enjoyment of these eyepieces I think, reduces glare and stops blackouts because you can easily get your eye in the right place.

[Alan White]

19 hours ago, Piero said:

Mine has a removable barrel but everything else is stuck in place. 

Piero you might be able to soften the remaining cement with Baader Wonder Fluid,
it not only dissolves crud on lenses....  oh yes I speak from experience here on a very locked up old manual camera lens.