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Equipment Discussions >> Eyepieces

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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Has Tele Vue Forsaken Long Focal Lengths?
      #5648306 - 01/28/13 02:15 PM

Some of you may recall a recent thread on this forum 22 pan vs 22t4. Once again it made me aware that I need to evaluate what I am using in that focal range. Currently, it is the venerable 22 Panoptic. It is superb in the longer focal ratio scopes I prefer. But my rational brain realizes I should acquire a 22 Nagler T4 for comparison, especially in light of how much I loved the 17T4.

I finally realized the root of my procrastination - the feeling that Tele Vue may be close to offering something substantially better in that range. After Delos there was speculation on a "Panoptic Makeover". Or perhaps even lighter Naglers (such as the revised 20mm model). But is that justified? I offer this timeline, based on product announcements in Tele Vue ads from Sky & Telescope:

- 22mm Nagler Type 4, June 1999;
- 31mm Nagler Type 5, December 1999;
- 26mm Nagler Type 5, October 2002;
- 24mm Panoptic, February 2003; and
- 41mm Panoptic, June 2003.

For the last ten years, Tele Vue has introduced nothing longer than 22mm. Most of their work has been in the short (and very short) focal lengths.

Could one imply that we are "due" to see some introductions in the longer lengths, or has Tele Vue lost interest?


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BillP
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Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: Jeff Morgan]
      #5648369 - 01/28/13 02:37 PM

Frankly, I don't think they have the interest. They can always argue that they have existing, excellent eyepieces in long focal lengths. 55 Plossl, 41/35 Pan, 31/26 Naglers, so why need more?

I of course agree with you. When new designs come out using latest glasses and coatings and production techniques, I feel that these new lines should as standard fare offer a 1.25" and 2" focal length that maximizes the barrel size. Neither the Ethos or the Delos do this and frankly, IMO it is a shame. Of course there may be the argument that the particular design is not practical to get to those longest focal lengths. To that I counter then offer a different design with the same optical parameters of ER and AFOV that does reach the max TFOV and brand it the same -- so give us a 72 degree Delos in 23mm or so and a 100 degree Ethos in 25mm or so. Don't care that the optical design might depart from the others as long as the AFOV, ER, and level of correction is maintained. This way we can build our eyepiece stalls with consistency. I know I was very happy when TV came out with the Delos line, then got bumbed when I would have to get a 24 pan to max my 1/25" capabilitiy. Don't want to do that and have a context switch like that...so not a candidate line of EPs for me.


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Grava T
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Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: BillP]
      #5648551 - 01/28/13 03:54 PM

I think most, if not all, Televue eyepieces are designed to be used with their own refractors or at least short focal length newtonians. Medium to high power eyepieces are more useful I would imagine. Hard to improve on the low power choices already offered by TV.

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Jon Isaacs
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Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: Grava T]
      #5648599 - 01/28/13 04:13 PM

Quote:

I think most, if not all, Televue eyepieces are designed to be used with their own refractors or at least short focal length newtonians. Medium to high power eyepieces are more useful I would imagine. Hard to improve on the low power choices already offered by TV.






Personally I am fine the existing eyepieces. I have a set of eyepieces from TeleVue that do the job. The 31mm Nagler is a fine eyepiece. To me, new and different are new objects in the sky to observe, new sites to observe from. A trip 5 hours down the road to the Baja Dark Skies Inn is going to make far more difference in what I see than a new eyepiece or two.

Jon


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BillP
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Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: Grava T]
      #5648646 - 01/28/13 04:34 PM

Quote:

I think most, if not all, Televue eyepieces are designed to be used with their own refractors or at least short focal length newtonians. Medium to high power eyepieces are more useful I would imagine. Hard to improve on the low power choices already offered by TV.




Hmmm...

1. Is the 24mm Panoptic improvable (as TV's max TFOV 1.25" wide field eyepiece)? I would say easily yes! Eye relief is way too short on this eyepiece. Needs to be 20mm. So there's a much needed improvement.

2. 41Pan/31T5 - Are these both entirely "perfect"? Nope. First off...they are massive and heavy. Improvements can be to lighten them and decrease their physical size. Plus, I need a 2" 100 degree eyepiece that gives widest TFOV capable with a 2" barrel. So not necessarily an improvement of these as much of a missing eyepiece.

Always room for improvement.


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turtle86
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Reged: 10/09/06

Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: BillP]
      #5648705 - 01/28/13 04:57 PM

I really would've liked a 25mm Ethos but I'm pretty happy with the 31mm Nagler. It sure seemed stupid big when I first got it but I've since gotten used to its size and weight. I've definitely gotten accustomed to its great wide field views.

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Jon Isaacs
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Reged: 06/16/04

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Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: BillP]
      #5648709 - 01/28/13 04:58 PM

Quote:

Plus, I need a 2" 100 degree eyepiece that gives widest TFOV capable with a 2" barrel. So not necessarily an improvement of these as much of a missing eyepiece




I am OK with 82 degree eyepieces. ES filled in the 25mm 100 degree. I am not sure there is room in the barrel for TeleVue to build an eyepiece 100 degree 25mm of sufficient quality to please Uncle Al. The 31mm Nagler uses all of a 2 inch barrel but only has an effective field stop diameter of 42mm.

In any event, I don't "need" any eyepieces but they are fun to have.

Jon


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BillP
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Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: Jon Isaacs]
      #5648738 - 01/28/13 05:12 PM

Quote:

I am not sure there is room in the barrel for TeleVue to build an eyepiece 100 degree 25mm of sufficient quality to please Uncle Al.




I have heard that expressed before. However, another way of saying that is "I can't make a 25mm 100 degree eyepiece of sufficient quality." If they really can't make it then should they be considered a leader in the industry? Can't have it both ways...I'm a leader and I can't do stuff so let other innovate...but I'm the leader, etc. Contradictory.


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tomcody
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Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: BillP]
      #5648773 - 01/28/13 05:26 PM



1. Is the 24mm Panoptic improvable (as TV's max TFOV 1.25" wide field eyepiece)? I would say easily yes! Eye relief is way too short on this eyepiece. Needs to be 20mm. So there's a much needed improvement.




That's only your opinion, I find 15mm eye relief to be Perfect! If you want 20mm? buy a Delos.
Rex


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Mike W
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Reged: 04/30/06

Loc: Upstate NY
Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: BillP]
      #5648789 - 01/28/13 05:34 PM

I agree on the eye relief ( there's worse offenders for sure) but I don't wonder if increasing the eye relief wouldn't also increase the size. As a favorite for binoviewers as they are, they might shoot themselves in the foot.
Quote:

Quote:

I think most, if not all, Televue eyepieces are designed to be used with their own refractors or at least short focal length newtonians. Medium to high power eyepieces are more useful I would imagine. Hard to improve on the low power choices already offered by TV.




Hmmm...

1. Is the 24mm Panoptic improvable (as TV's max TFOV 1.25" wide field eyepiece)? I would say easily yes! Eye relief is way too short on this eyepiece. Needs to be 20mm. So there's a much needed improvement.

2. 41Pan/31T5 - Are these both entirely "perfect"? Nope. First off...they are massive and heavy. Improvements can be to lighten them and decrease their physical size. Plus, I need a 2" 100 degree eyepiece that gives widest TFOV capable with a 2" barrel. So not necessarily an improvement of these as much of a missing eyepiece.

Always room for improvement.




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rockethead26
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Reged: 10/21/09

Loc: Arizona, USA
Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: tomcody]
      #5648805 - 01/28/13 05:40 PM

Quote:



1. Is the 24mm Panoptic improvable (as TV's max TFOV 1.25" wide field eyepiece)? I would say easily yes! Eye relief is way too short on this eyepiece. Needs to be 20mm. So there's a much needed improvement.




That's only your opinion, I find 15mm eye relief to be Perfect! If you want 20mm? buy a Delos.
Rex




Uh, they don't make a 24mm Delos. I think that's the point.


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tomcody
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Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: rockethead26]
      #5648819 - 01/28/13 05:45 PM

Quote:

Quote:



1. Is the 24mm Panoptic improvable (as TV's max TFOV 1.25" wide field eyepiece)? I would say easily yes! Eye relief is way too short on this eyepiece. Needs to be 20mm. So there's a much needed improvement.




That's only your opinion, I find 15mm eye relief to be Perfect! If you want 20mm? buy a Delos.
Rex




Uh, they don't make a 24mm Delos. I think that's the point.



And they don't make a 24 Panoptic with 20mm of eye relief. It would make more sense to suggest a 24mm Delos , a line with constant 20mm eye relief than to change a proven design with a good following. That's the point.
Rex


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sniperpride
super member


Reged: 01/04/12

Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: tomcody]
      #5648944 - 01/28/13 06:43 PM

Except that they dont intend to make a Delos at longer focal lengths.
The point of this was to upgrade current existing focal lengths. Panoptics, long FL naglers.


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Starman1
Vendor (EyepiecesEtc.com)
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Reged: 06/24/03

Loc: Los Angeles
Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: BillP]
      #5648979 - 01/28/13 06:59 PM

Quote:

Frankly, I don't think they have the interest. They can always argue that they have existing, excellent eyepieces in long focal lengths. 55 Plossl, 41/35 Pan, 31/26 Naglers, so why need more?

I of course agree with you. When new designs come out using latest glasses and coatings and production techniques, I feel that these new lines should as standard fare offer a 1.25" and 2" focal length that maximizes the barrel size. Neither the Ethos or the Delos do this and frankly, IMO it is a shame. Of course there may be the argument that the particular design is not practical to get to those longest focal lengths. To that I counter then offer a different design with the same optical parameters of ER and AFOV that does reach the max TFOV and brand it the same -- so give us a 72 degree Delos in 23mm or so and a 100 degree Ethos in 25mm or so. Don't care that the optical design might depart from the others as long as the AFOV, ER, and level of correction is maintained. This way we can build our eyepiece stalls with consistency. I know I was very happy when TV came out with the Delos line, then got bummed when I would have to get a 24 pan to max my 1/25" capabilitiy. Don't want to do that and have a context switch like that...so not a candidate line of EPs for me.



1) The Panoptic line (41/35/27/24/19) complements the Delos (17.3/14/12/10/8/6/4.5/3.5), so why should TV come out with longer Delos?
2) A Delos 23 would be 2" or have vignetting issues.
3) A 25 Ethos (not changing the internal design) would have poorer edge correction and significant vignetting, which TV won't do, not to mention being ridiculously expensive if the same glass types were used (not to mention weight). ES made a lot of compromises to introduce the 25 (it doesn't have the same internal design as the 20/14/9), and the market may say those compromises were justified and OK, but TeleVue has already said they won't. So you won't see a 25 Ethos.
4) Likewise, the Nagler line is fairly complete. Mix T5s and T6s, and you have: 31/26/20/16/13/11/9/7/5/3.5/2.5 which really kind of covers it.

With positive/negative eyepiece designs now dominating the market in wide and ultrawide fields, you have to look at how an eyepiece would maximize the field stop for the barrel diameter. Would a 1.25" 23mm Delos be practical if it had to be, say, several ounces heavier and a couple inches larger in diameter and maybe a lot more expensive? Then everyone would say, "I don't see why anyone would get this when a 21 Ethos has a wider true field and weighs less......"
Sometimes the largest practical field stop for a given diameter is smaller than the inside diameter of the barrel. Even Pentax went with 2" for 30 and 40mm XWs. The 31mm Nagler has a 42mm field stop when the inside diameter of the barrel is at least 46.5mm. Would you contemplate buying a 31mm eyepiece a pound heavier and 2" larger in diameter just to get a slightly larger field stop? Or an eyepiece with vignetting and poorer edge correction to keep the size the same but expand the field stop?

Probably not. And neither would I if I knew that compromise had been made.

I could see some company, and it probably would be TeleVue, coming out with a line of long eye relief 82 degree eyepieces. That would heavily expand the market for 82 degree eyepieces, whether they had field stops of the I.D. of the barrels or not.

Edited by Starman1 (01/28/13 07:00 PM)


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Paul G
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Loc: Freedonia
Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: tomcody]
      #5649093 - 01/28/13 07:52 PM

Quote:



1. Is the 24mm Panoptic improvable (as TV's max TFOV 1.25" wide field eyepiece)? I would say easily yes! Eye relief is way too short on this eyepiece. Needs to be 20mm. So there's a much needed improvement.




That's only your opinion, I find 15mm eye relief to be Perfect!
Rex




I also find it very comfortable, no need for more eye relief, particularly if that means the eyepiece would be physically larger.


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Grava T
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Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: BillP]
      #5649163 - 01/28/13 08:19 PM

Quote:

Quote:

I think most, if not all, Televue eyepieces are designed to be used with their own refractors or at least short focal length newtonians. Medium to high power eyepieces are more useful I would imagine. Hard to improve on the low power choices already offered by TV.




Hmmm...

1. Is the 24mm Panoptic improvable (as TV's max TFOV 1.25" wide field eyepiece)? I would say easily yes! Eye relief is way too short on this eyepiece. Needs to be 20mm. So there's a much needed improvement.

2. 41Pan/31T5 - Are these both entirely "perfect"? Nope. First off...they are massive and heavy. Improvements can be to lighten them and decrease their physical size. Plus, I need a 2" 100 degree eyepiece that gives widest TFOV capable with a 2" barrel. So not necessarily an improvement of these as much of a missing eyepiece.

Always room for improvement.




Point taken and I guess there is always room for improvement but it's like re-recording "Stairway to Heaven" to make it better. Why would you want to?


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johnnyha
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Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: BillP]
      #5649327 - 01/28/13 09:48 PM

Quote:

I have heard that expressed before. However, another way of saying that is "I can't make a 25mm 100 degree eyepiece of sufficient quality." If they really can't make it then should they be considered a leader in the industry? Can't have it both ways...I'm a leader and I can't do stuff so let other innovate...but I'm the leader, etc. Contradictory.




I think you might be confusing quality with quantity Bill. The decision to NOT make the 25E is what makes Nagler an industry leader. The 21 Ethos was an innovation, the 25 ES 100 is a knockoff that makes compromises as Don has pointed out, compromises that TV is unwilling to make.


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John F
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Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: Jeff Morgan]
      #5649426 - 01/28/13 10:51 PM

Jeff,

I've owned both the 22mm Pan and T4 Nagler in the past. Yes, the T4 has a larger and somewhat more immersive field than the Pan does. However, it weighs 8 ounces more and has that click-stop eyeguard which some observers don't like.

The Pan on the other hand still has a fairly large TFOV and AFOV, 15mm of eye relief, and is not too large or heavy. And all around, it is one of the most relaxing to observe with eyepieces that I've ever used.

If you already have one, and have been very pleased with it, count yourself fortunate and just keep using it. If you get the 22mm T4 then you may start having doubts about whether you should have got 21mm Ethos instead.

John Finnan


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faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: johnnyha]
      #5649468 - 01/28/13 11:20 PM

Quote:

Quote:

I have heard that expressed before. However, another way of saying that is "I can't make a 25mm 100 degree eyepiece of sufficient quality." If they really can't make it then should they be considered a leader in the industry? Can't have it both ways...I'm a leader and I can't do stuff so let other innovate...but I'm the leader, etc. Contradictory.




I think you might be confusing quality with quantity Bill. The decision to NOT make the 25E is what makes Nagler an industry leader. The 21 Ethos was an innovation, the 25 ES 100 is a knockoff that makes compromises as Don has pointed out, compromises that TV is unwilling to make.




Industry leaders innovate and push the envelope (like TV did when they created the first Ethos). Sometimes compromizes have to be accepted (like Nagler zooms don't have 82 AFOV).


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Starman1
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Loc: Los Angeles
Re: Has Tele Vue Forsaken Long Focal Lengths? new [Re: faackanders2]
      #5649541 - 01/29/13 12:08 AM

Nearly every eyepiece has compromises of some sort, at least in one or more design parameters.
There is no such thing as a perfect eyepiece, both in terms of personal preferences (eye relief, apparent field), design (weight, size, complexity of manufacture), and optical parameters (amount of AMD, RD, astigmatism, lateral color, transmission, etc.).
I've been doing this a while (50 years this year), and I've never seen the perfect eyepiece. And if some company made it, it would be too expensive for any of us to afford it anyway.
So we deal with eyepieces that have imperfections; some imposed by the imperfect viewing device (the eye) and others by the laws of optics (the inability to solve for both zero AMD and zero RD at the same time), and still others the marketplace (price, weight, size).

I last worked on the Eyepiece Buyer's Guide in 2009 and there were nearly 1600 different eyepieces available from 2mm to 56mm (and a few specialty eyepieces even longer), and I've started the process of re-doing it for 2013 and along the way I'm discovering a lot of companies have disappeared. Very few companies have expanded their lines.

I hope TeleVue continues to innovate. I hope that many Chinese companies successfully market their wares. There are a few up-and-comers. I'm not sure we ever needed the plethora of offerings that were around in 2009, but I don't want to see too major a drop in the number of choices, either. We all benefit from innovation and competition. State of the Art will always cost more, and it will never be for everyone. But with larger production comes lower costs and more sales, so perhaps we could deal with a few less players and fewer choices. Then, perhaps, our favorite companies might make a profit and keep innovating.


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