Televue

[RT65CB-SWL]

14 hours ago, Philip R said:

...the 'mythical' Apollo 11.

 

12 hours ago, Mr Spock said:

They are real - if you can find one.

So, if you thought they were a myth, I can say for certain you were mythtaken...

I know they exist and I was trying to add a little humour... but at £1500GBP and limited to 300 pieces worldwide... they may as well be 'mythical'.

Edited August 27, 2021 by Philip R

[Deadlake]

8 hours ago, Louis D said:

Was TeleVue considering having Starlight Instruments CNC machine them at that price?

Come on Starlight would charge twice that price. 😀 it’s nearly $200 for a finder holder.

[Deadlake]

8 hours ago, John said:

That works fine where a 2 inch barrel is added to a fixed 1.25" barrel.

For 1.25 inch eyepieces the replacement barrel would also have to contain the lower optical set which many of the Tele Vue ranges use. Either that or a complete re-design of the lower half of the eyepiece would be needed to provide a lower optical element housing and a 1.25 inch sleeve to fit (and lock) over that, either undercut or not according to the owners preference.

 

 

APM EP’s have a 1.25 to 2” adapter that screws in. For EP’s less then 20 mm this solution works fine and for APM and UO works from a cost perspective. 


Maybe a similar adapter could be 3D printed?

Edited August 27, 2021 by Deadlake

[JeremyS]

10 hours ago, Don Pensack said:

TV looked into this and over a decade ago the barrels were about $50 apiece at TeleVue's cost.

Then there is the labor of changing the barrel.

 

This might be a solution for a machinist who can make his own, but it's not commercially viable.

 

Thank Don. I was thinking I’d be prepared to pay 10% extra for another barrel, or £50, which I would fit if they were simply screw fit

Do you know when and why they changed the design of the barrel undercuts?

Also, I notice the barrel of my Pan 24 has tarnished a little. I’ve noted other people make this comment (can’t remember which TV EP). Do you know why this is? All stored in same way in same case. The Pan is the oldest.

[JeremyS]

@Don Pensack I tried to take a pic to show the slight off colour on the Pan 24 cf say the Pan 19. The difference is very subtle and not sure you can see here. Maybe slightly matte rather than tarnished

[John]

2 hours ago, Deadlake said:

APM EP’s have a 1.25 to 2” adapter that screws in. For EP’s less then 20 mm this solution works fine and for APM and UO works from a cost perspective. 


Maybe a similar adapter could be 3D printed?

The Ethos SX 4.7 and 3.7 use just that approach as well. I was using my 4.7 last night and it's a great high power eyepiece with my 12 inch dob

I could see that a smooth 2 inch barrel option could be provided at a reasonable cost.

For 1.25 inch eyepieces (eg: the Panoptics that @JeremyS pictures it's more difficult unless folks simply add a smooth sided 1.25 - 2 inch adapter and leave it on the eyepiece. Something like this:

https://www.firstlightoptics.com/adapters/moonlite-2-to-125-low-profile-eyepiece-adapter.html

 

 

[markse68]

21 minutes ago, JeremyS said:

@Don Pensack I tried to take a pic to show the slight off colour on the Pan 24 cf say the Pan 19. The difference is very subtle and not sure you can see here. Maybe slightly matte rather than tarnished

why don’t premium eps use stainless steel for the nose piece instead of the traditional plated brass? would be much more durable.

Mark

[Mark at Beaufort]

Just a general comment about undercuts especially using the Ethos range. I use the Baader 28mm finetuning rings which gives 2" smooth insets.

[Louis D]

4 hours ago, John said:

The Ethos SX 4.7 and 3.7 use just that approach as well. I was using my 4.7 last night and it's a great high power eyepiece with my 12 inch dob

It appears that the TV Apollo 11 also comes with a 2" sleeve:

Maybe it would have been $50 cheaper without it?

[Don Pensack]

16 hours ago, Louis D said:

And your point is what?  I never claimed they were.  Besides, the AF70 is available under other brands in Europe.  The B&L eyepieces were long since discontinued when I bought them off ebay 15 years ago, so the point is moot with them.  They're probably 1960s or 1970s vintage.  The 17mm NT4 was just discontinued and is still listed as in stock a few places.

Sorry, the only point was that comparing discontinued eyepieces for edge sharpness that are not available for purchase is useful information only to the purchaser of used eyepieces.

You're right, though, that there are probably 17mm Naglers still in stock at various places, and that the 17mm Astrotech is available under other labels.

[Don Pensack]

6 hours ago, JeremyS said:

Thank Don. I was thinking I’d be prepared to pay 10% extra for another barrel, or £50, which I would fit if they were simply screw fit

Do you know when and why they changed the design of the barrel undercuts?

Also, I notice the barrel of my Pan 24 has tarnished a little. I’ve noted other people make this comment (can’t remember which TV EP). Do you know why this is? All stored in same way in same case. The Pan is the oldest.

The tapered edge to the bottom lip of the undercut was several years ago, though I couldn't tell you exactly when.

They did so to get the eyepiece to remove a little easier by shoving the brass split ring aside on removal and to get around the lip above the brass split ring.

 

TeleVue lower barrels have been chrome plated brass for a long time, and chrome is usually put on top of nickel to adhere better.  Nickel will dull with time, and, if the chrome plating is very thin,

may cause the surface to dull, perhaps irregularly.  You might try a little jeweler's polishing rouge (aka Simichrome polish) to buff it up if you want.

 

TeleVue said that they had a few reasons for not wanting to offer smooth barrels for the eyepieces as an option:

--the barrels were expensive--about $50 at their cost in the volume they contemplated

--a large number of different barrel sizes and shapes

--they didn't have enough manpower in the office to do the switch--especially if it proved popular

--it would be a marketing admission that not everyone liked the undercuts

--it might result in more damaged eyepieces, which could tarnish their reputation (though, I would argue, not any more than the undercuts in the first place)

Reasons 3 and 4 are why they couldn't switch back, either, in addition to:

--making old stock, a lot of which is at the dealers, obsolete or less desirable

--meaning they would have to have double inventory if the smooth barreled versions came from the factory, which they couldn't afford

--meaning the dealers would have to carry dual inventory as well if some people preferred the undercuts (and some people do).

 

So, we aren't going to see the disappearance of undercuts in eyepiece barrels.  But at least an attempt was made to modify the undercuts to make the eyepieces easier to remove.

That still leaves the incompatibility problem.  Brass split rings, collets, et al.  are designed to hold smooth barrels securely.  Undercuts (cylindrical or conically tapered) are designed to work best with thumb screws.

If you see the issues, then you can do what I did--simply use thumbscrews and leave marks (or use nylon or nylon tipped thumbscrews), or look for smooth barrels (not many of them, though).

 

[Don Pensack]

6 hours ago, John said:

The Ethos SX 4.7 and 3.7 use just that approach as well. I was using my 4.7 last night and it's a great high power eyepiece with my 12 inch dob

I could see that a smooth 2 inch barrel option could be provided at a reasonable cost.

For 1.25 inch eyepieces (eg: the Panoptics that @JeremyS pictures it's more difficult unless folks simply add a smooth sided 1.25 - 2 inch adapter and leave it on the eyepiece. Something like this:

https://www.firstlightoptics.com/adapters/moonlite-2-to-125-low-profile-eyepiece-adapter.html

 

 

There are a number of smooth-sided adapters out there, some of which don't require the slit in the focuser like the Moonlite.

The new 7mm APM XWA eyepiece has a threaded on 2" adapter with smooth sides, and the 1.25" barrel underneath is also smooth sided.

But that could be done because it was a new eyepiece and was ordered that way.

 

[Don Pensack]

6 hours ago, markse68 said:

why don’t premium eps use stainless steel for the nose piece instead of the traditional plated brass? would be much more durable.

Mark

Stainless steel doesn't have that shiny chrome look, though.

 

The Stellarvue Optimus eyepieces do have stainless steel lower barrels, and they are not unique.

 

However, as a result, they are a lot heavier than the all-aluminum APM versions of the same eyepieces.

[Don Pensack]

1 hour ago, Louis D said:

It appears that the TV Apollo 11 also comes with a 2" sleeve:

Maybe it would have been $50 cheaper without it?

Possibly, since only 300 were made (no economy of scale).

It points out that a dual-size eyepiece should have a removable skirt if the eyepiece can be used as a 1.25".

[markse68]

1 hour ago, Don Pensack said:

Stainless steel doesn't have that shiny chrome look, though.

 

The Stellarvue Optimus eyepieces do have stainless steel lower barrels, and they are not unique.

 

However, as a result, they are a lot heavier than the all-aluminum APM versions of the same eyepieces.

maybe but it’s a wear surface so ss would be better. Brass is heavier than ss also.

Mark

[Louis D]

33 minutes ago, markse68 said:

maybe but it’s a wear surface so ss would be better. Brass is heavier than ss also.

Mark

Brass is barely heavier than SS, especially as either compared to aluminum or delrin.  However, SS could be made with thinner walls than brass to yield similar strength characteristics.  In that case, it would definitely be lighter overall than brass.

1 hour ago, Don Pensack said:

Stainless steel doesn't have that shiny chrome look, though.

I guess you haven't seen all the nice SS jewelry coming out of China lately.  I've bought quite a few bands and faux gemstone rings through ebay for cheap, and the SS they're using takes a very high polish and doesn't seem to tarnish at all in my experience.  It's a different "whiteness" from sterling silver, but still quite mirror-like.

[jetstream]

I like the chromed brass myself, it gives them a solid build quality feel. Others must like it too judging from the popularity of Televue eyepieces.

At the other end of the scale is Baaders BCO series- the complaint there is the "cheap" build quality and that they need more heft like the Fuji orthos- KK, astrohutech etc.

I see no reason for change in either.

[Louis D]

It reminds me of the original IBM PC keyboards that had a hefty steel plate in the bottom.  At some point, it was removed and everyone immediately equated the lack of heft to being poorer quality despite everything else being the same.

[globular]

I'm going to use that one with my doctor.  When he next says "you could do with losing some weight" I'll say "my heft is a sign of quality".

[Don Pensack]

5 hours ago, Louis D said:

Brass is barely heavier than SS, especially as either compared to aluminum or delrin.  However, SS could be made with thinner walls than brass to yield similar strength characteristics.  In that case, it would definitely be lighter overall than brass.

I guess you haven't seen all the nice SS jewelry coming out of China lately.  I've bought quite a few bands and faux gemstone rings through ebay for cheap, and the SS they're using takes a very high polish and doesn't seem to tarnish at all in my experience.  It's a different "whiteness" from sterling silver, but still quite mirror-like.

Interesting.  My wedding ring is made from Silicon Carbide and is heavier than gold.

I have a couple other rings made from titanium and they, too, have a high polish.

There are a lot of materials that eyepiece barrels could be made from, but aluminum is still the most practical because of low weight and low cost.

Speaking of lightweight, imagine beryllium or magnesium as a material--talk about light.

[Louis D]

Vintage binoculars were sometimes made with magnesium frames and touted how light weight they were.  Despite this, they were very heavy by modern binocular standards, probably due to often using oversized porro prisms to allow for very wide angle views.

I've also bought some of the tungsten carbide (I think that's what you meant) rings.  They are pretty awesome.  They can't normally be scratched (Mohs 9.0) and the dark reflection is really cool looking.  Their heft is pretty incredible as well.

Silicon carbide is fairly light, actually less dense than diamond.  It is known as Moissonite in the gem trade.  It has lots of industrial uses when not gem grade thanks to its extreme hardness (9.5 on the Mohs scale).  However, it is not a metal.

I have a brushed titanium band that looks really industrial thanks to that metal's rather unappealing shade of gray.  I never bought another because of that.

[Voyager 3]

6 hours ago, globular said:

"my heft is a sign of quality".

It was that way among the medieval aristocrats of France !!!

[markse68]

9 hours ago, jetstream said:

Others must like it too judging from the popularity of Televue eyepieces.

🤔 do people really buy eyepieces for the barrels? I doubt many ever think about it until they damage the chrome. I’ve seen older eps where the chrome has worn to reveal the brass underneath and i’m pretty sure I’ve seen an old TV plossl like that. At least with SS you could re-polish/brush if you wanted to rejuvenate their looks. No I think it’s a cost thing which is why i question its use in premium cost eps. Brass is much easier to machine and therefore cheaper, though with modern CNC machines that shouldn’t really make much difference.

 

47 minutes ago, Louis D said:

Vintage binoculars were sometimes made with magnesium frames and touted how light weight they were. 

My Bausch and Lomb Zephyr are delightfully featherweight- maybe not as light as some modern plastic bodied bins but lovely light bright and incredibly sharp vintage bins. They’re magnesium bodied. Not very wide angle though but that’s more to do with the eps.

Not sure magnesium would be a great material for this though- it corrodes quite readily I think, is a bit soft and you can’t hard anodise it like aluminium. I really like the BCOs basic yet well engineered quality 👍 That hard anodising is pretty durable though it can chip if impacted.

Mark

[Stu]

On 27/08/2021 at 01:26, Philip R said:

So, if you thought they were a myth, I can say for certain you were mythtaken...

 

On 27/08/2021 at 01:26, Philip R said:

I know they exist and I was trying to add a little humour...

@Philip R I think Don was trying to respond in kind, check the ‘mythtaken’ comment 😀😀👍

[Zermelo]

13 hours ago, Don Pensack said:

imagine beryllium

"that's a niche topic", I thought, and then I searched the forum to find no fewer than 25 posts mentioning beryllium (excluding this one), ranging from nucleosynthesis through to the James Webb Telescope, via golf clubs. I was going to point out that its nasty toxicity might preclude its use in eyepieces, but that's also been mentioned before, more than once.