87 replies to this topic

[Lentini]

TeleVue makes some great telescopes.

One oldie but goodie is the Oracle 3… A triplet that has been impressing the heck out of me. It takes magnification like a champ. Resolves tight doubles like a pro.

Planets look great.

A stellar scope that has done nothing but impress me.

I cast my vote that TeleVue start a refreshed lineup of triplets from 76mm to 101mm. What do you say?

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[Jon Isaacs]

Triplets are not Televue's thing.  In the smaller sizes, doublets work well.  In the larger sizes, the NP series has excellent color correction and wide, flat fields of view.  That's TeleVue's thing.

 

The Oracle (1987) was introduced at a time when ED Glasses like FPL-51 and FPL-53 were not available.  ED glasses were game changers.

 

There are other manufacturers that produce triplets. 

 

Jon

Edited by Jon Isaacs, 25 May 2025 - 03:12 AM.

[scotsman328i]

TeleVue makes some great telescopes.

One oldie but goodie is the Oracle 3… A triplet that has been impressing the heck out of me. It takes magnification like a champ. Resolves tight doubles like a pro.

Planets look great.

A stellar scope that has done nothing but impress me.

I cast my vote that TeleVue start a refreshed lineup of triplets from 76mm to 101mm. What do you say?

I’ve heard nothing but great things of the Oracle and Genesis (both SDF and non-SDF) models.

 

Jon is correct with what he is saying though, these were links in the evolutionary chain of Televue’s telescope designs, and where we are today with their lens technologies. Televue have whittled their line up now to the 60, 76, 85, NP 101 and NP127. The Televue emphasis and vision seems to have evolved more into eyepiece design and ocular lens technologies far more than their telescope line up anymore. However, the current line up of available apertures (both with and without NP) are still legends. The NP line (101 and 127) ended up being the future of the older Televue triplet design with it’s full-aperture doublet objective up front, and sub-aperture doublet in the rear.

Edited by scotsman328i, 25 May 2025 - 06:23 AM.

[25585]

If TV brought out a 4" fluorite doublet, that would be cool! Not many of those, Borg & Takahashi. A F9 or F10 would be super cool, Steinheil optics please, Canon Optron. 

[NC Startrekker]

As Jon noted, it’s important to carve out your niche in a business and stick with it. APO triplets are a dime a dozen these days. If you want premium, look to AP, TEC or Tak among others. If you are willing to set pedigree aside, there are any number of options available by both Asian and European manufacturers. So many companies make the mistake of trying to be all things to all people. Regrettably this often leads to mediocrity and that to failure. To Uncle Al’s credit, he and Televue have done a pretty good job at discovering those niches and perfecting products that serve them. As a result, I can’t think of too many failures along the way. It seems that TV only discontinues a product when either they come up with a better replacement or it ultimately comes in competition with another of its own product lines (think eyepieces).

[Jon Isaacs]

 

To Uncle Al’s credit, he and Televue have done a pretty good job at discovering those niches and perfecting products that serve them. As a result, I can’t think of too many failures along the way. It seems that TV only discontinues a product when either they come up with a better replacement or it ultimately comes in competition with another of its own product lines (think eyepieces).

 

Al Nagler had a vision of what amateur astronomy could be.  He has remained true to that vision and the world of amateur astronomy has been transformed buy his vision.. He didn't carve out a niche, he created it and where he first went, many, other observers and manufacturers have followed.

 

Jon

Edited by Jon Isaacs, 25 May 2025 - 01:55 PM.

[Highburymark]

The TeleVue design ethos for its non-imaging scopes is very much focused on portability, ruggedness and user-friendliness for night and daytime observing. The Al Nagler article on TV’s website about apo design explains why triplets don’t chime with this philosophy. The three ED doublets between 60mm and 85mm do their job very well, in my view. I’ve just had a couple of perfect nights with my TV85 in southern Morocco - even at 225x on Vega, the TV85 produced exceptional, colour-free views. I’ve seen a little bit of false colour before with this scope on bright stars, but this week showed how good the 85’s optics are.

[Lentini]

So are the NPs considered quadruplets, or double-doublets? 

[25585]

So are the NPs considered quadruplets, or double-doublets? 

Modified Petzvals.

[Mike W]

NP-Nagler Petzval

[scotsman328i]

So are the NPs considered quadruplets, or double-doublets? 

I would think that TeleVue NP refractors would be considered quadruplets, not twin doublets. Since they use a four-element Petzval-type optical design, consisting of two air-spaced doublet groups, it kinda falls under a quad of lenses. The superior design helps to correct chromatic aberration and provides a flat field, making them pretty popular with the visual crowd and the astrophotography crowd alike.

Edited by scotsman328i, 25 May 2025 - 10:37 AM.

[Lentini]

Sounds like I need to refocus my desire for a bigger triplet and move right to an NP Petzval!

Edited by Lentini, 25 May 2025 - 10:49 AM.

[Terra Nova]

Al first sought to be a game changer with his Prototype MPT, a 5” fast Petzval with a built in iris-diaphragm with user-selected F-stop setting. This evolved into the first 4” Genesis. His guiding strategy was to take the common-at-the-time long refractor and shorten it while preserving its optical integrity as best he could to make it more ergonomically friendly and more easily portable. This evolved into the Genesis SDF, then the TV101, then the NP101 (and 127), while throughout this evolution, continuing to improve the color correction and still offer a flat field. He has definitely accomplished this goal. IMO, that’s where his telescope legacy lies. I think that his smaller doublets (and the very briefly offered 102), were and are produced mostly to stay relevant in the marketplace by offering excellent optics and well-built mechanics, made in the USA. But it’s his Petzvals, since the first MPT to a current NP101 or 127, that show where his heart and mind really are.

Edited by Terra Nova, 25 May 2025 - 10:53 AM.

[Astroman007]

While we're dreaming, I'd like to see a 6" Tele Vue refractor. Could be a triplet, maybe even a fine doublet. Not an NP design, as that would be prohibitively expensive today.

[Mike W]

4" doublet.

[Illinois]

I would like TeleVue 102 f8.6 with feathertouch focuser back!  120mm f8  with feathertouch forcuser would be nice.  Al Nagler love very fast scopes and low power.  

[Jon Isaacs]

I would like TeleVue 102 f8.6 with feathertouch focuser back!  120mm f8  with feathertouch forcuser would be nice.  Al Nagler love very fast scopes and low power.  

 

Other manufacturers make F/8 and slower refractors. TeleVue makes refractors that are designed to complement their eyepieces... 

 

Jon

[RichA]

Triplets are not Televue's thing.  In the smaller sizes, doublets work well.  In the larger sizes, the NP series has excellent color correction and wide, flat fields of view.  That's TeleVue's thing.

 

The Oracle (1987) was introduced at a time when ED Glasses like FPL-51 and FPL-53 were not available.  ED glasses were game changers.

 

There are other manufacturers that produce triplets. 

 

Jon

I think  the Oracle must have some ED glass because even as a triplet it wouldn't have the correction as good as a TV-76 (which is does) which is an FPL-53 or equivalent doublet. 

[Spikey131]

I think  the Oracle must have some ED glass because even as a triplet it wouldn't have the correction as good as a TV-76 (which is does) which is an FPL-53 or equivalent doublet. 

I’m not sure about that….

 

Ed Ting, in a review of the Oracle, indicated that the TV76 had better optics.

[Heywood]

About 20 years ago, Tele Vue had an online chat (I forget exactly how it was done), and I inquired then about larger Tele Vue apo's other than the NP-127.  The Naglers made it clear that would never happen.

[Mike W]

About 20 years ago, Tele Vue had an online chat (I forget exactly how it was done), and I inquired then about larger Tele Vue apo's other than the NP-127.  The Naglers made it clear that would never happen.

Televue 140.

[Spikey131]

About 20 years ago, Tele Vue had an online chat (I forget exactly how it was done), and I inquired then about larger Tele Vue apo's other than the NP-127.  The Naglers made it clear that would never happen.

Tele Vue is an eyepiece company that makes a few cool telescopes.  Kinda like Astro-Physics is a mount company that makes a few cool telescopes.  I don’t think either one would survive on telescope sales, but I am glad that they are doing what they are doing.

[Mike W]

https://televue.com/...e-140-re-built/

[Heywood]

Televue 140.

 

That was long before the online chat I mentioned.

[Jon Isaacs]

That was long before the online chat I mentioned.

 

From what I understand, the TV-140 is difficult to keep collimated. 

 

Jon