Vixen LVW vs Pentax XW vs Delos

[John]

Celestron used to offer re-branded Vixen items as well. I have a theory that the Nagler zooms are also Vixen made but I've only scant evidence for that - not much more than a hunch based on owning a few really. Many years ago I owned a 4" F/9.8 refractor on a GOTO eq mount. It was branded as the Bresser Uranus but was actually a Vixen SP102M on a Super Polaris mount with Vixen Skysensor GOTO and all in the matt black colour scheme that Bresser used back then.

I think TV's decision not to take out patents is to do with the cost of defending them, which is prohibative for what is still a relatively small company. ES seemed to copy the Ethos design despite any patent that might have been on it:

http://www.svenwienstein.de/HTML/es_14mm_ethos_13mm_English.html

 

[Louis D]

1 hour ago, 25585 said:

TV no longer patenting their designs? Are they no longer unique enough, or maybe only some.

Because patenting eyepieces essentially tells cloners how to make a copy of your eyepiece.  All they have to do is make a slight change not covered by one of the variations mentioned in the patent and they're pretty much in the clear.  TV tried suing Meade I believe over their 4000 series UWA and possibly SWA eyepieces.  After much lawyer money spent, they got no where.  As a result of this, they decided to go the route of trade secrets.  You don't have protection from copying (witness the ES-100 and Nikon NAV-HW basically copying the Ethos), but you also don't just tell them what your innovation was.  They have to reverse engineer it as best they can.  Nikon did a much better job of it than did ES, BTW.

Clearly the Lunt/Myriad 100 series are another beast altogether given how light they are compared to the Ethos on a per focal length basis and yet maintain excellent correction.  We can surmise they started with the other 100 degree designs as reference points and then went to the (figurative) drawing board to build on those innovative designs.  Also, ES did something similar by combining the innovations of the Ethos and Delos to create their ES-92 line from scratch.

TV continues to innovate with Paul Dellechiaie as head designer now having designed the Ethos, Delos, and DeLite lines.  Without the Ethos he designed, I doubt there would be ES-100, ES-120, ES-92, Nikon NAV-HW, or Lunt/Myriad 100 eyepieces to choose from.  Who knows what he's working on next.

[Louis D]

1 hour ago, John said:

Celestron used to offer re-branded Vixen items as well. I have a theory that the Nagler zooms are also Vixen made but I've only scant evidence for that - not much more than a hunch based on owning a few really. Many years ago I owned a 4" F/9.8 refractor on a GOTO eq mount. It was branded as the Bresser Uranus but was actually a Vixen SP102M on a Super Polaris mount with Vixen Skysensor GOTO and all in the matt black colour scheme that Bresser used back then.

I have only a vague recollection about the Celestron/Vixen collaboration.  Thanks for noting it.  I knew nothing about Bresser since they're not sold over here to my knowledge.

The Nagler zooms (3-6mm and 2-4mm) were definitely Al Nagler designs.  I recall reading somewhere that when asked which design he was most proud of, he said it was his Nagler zooms because he managed to maintain a constant 50 degree field, parfocalness, and excellent correction all at once in them.  They are more than likely made in the Taiwanese TV factory along with the rest of the current TV eyepieces.

[F15Rules]

On 11/11/2017 at 13:51, 25585 said:

Excellent purchase! 

If I can't find a 22 LVW a 20 XW might be the next option, but it has varying pro & con write-ups. 

Why not try the ES 24mm 68?

I've owned one and really liked it. Like Alan I slightly prefer the LVW22 but I preferred the ES to the XW20 and it's a very well made, chunky EP with great optics for an excellent price. And it would fit in nicely between your LVW17 and NLVW 30mm ☺.

Dave

[Saganite]

40 minutes ago, F15Rules said:

Why not try the ES 24mm 68?

I've owned one and really liked it. Like Alan I slightly prefer the LVW22 but I preferred the ES to the XW20 and it's a very well made, chunky EP with great optics for an excellent price. And it would fit in nicely between your LVW17 and NLVW 30mm ☺.

Dave

+1 for the ES 68 DEG. 24mm, a lovely eyepiece, and I would have bought a pair for my binoviewer, had my IPD matched them. Definitely worth consideration.

[Paul73]

48 minutes ago, F15Rules said:

Why not try the ES 24mm 68?

I've owned one and really liked it. Like Alan I slightly prefer the LVW22 but I preferred the ES to the XW20 and it's a very well made, chunky EP with great optics for an excellent price. And it would fit in nicely between your LVW17 and NLVW 30mm ☺.

Dave

Weirdly, the ES82° is a far more engaging eyepiece than the 68° (a fine eyepiece but not in the Delos quality league). The field is flatter and obviously the extra 20% fov is nice. At 24mm this or the TV Panoptic would be my choice.

Paul

[Saganite]

26 minutes ago, Paul73 said:

Weirdly, the ES82° is a far more engaging eyepiece than the 68° (a fine eyepiece but not in the Delos quality league). The field is flatter and obviously the extra 20% fov is nice. At 24mm this or the TV Panoptic would be my choice.

Paul

I have a pair of 24mm Pans, as you know, and they are superb in a binoviewer, and that form of observing, I am dedicated to, but the ES 24 68 deg gave very little to the Pan 24, and I would have gladly used them had I been able to do so, and certainly the cost saving would have been very worthwhile. 

[YKSE]

10 hours ago, Louis D said:

You don't have protection from copying (witness the ES-100 and Nikon NAV-HW basically copying the Ethos)

TV continues to innovate with Paul Dellechiaie as head designer now having designed the Ethos, Delos, and DeLite lines.  Without the Ethos he designed, I doubt there would be ES-100, ES-120, ES-92, Nikon NAV-HW, or Lunt/Myriad 100 eyepieces to choose from.  Who knows what he's working on next.

There's no doubt that Televue has been very innovative about eyepieces design, but the above comments are border to streching, and even missleading IMHO.

1. Nikon NAV-HW:

This is the lens/groups about Nikon NAV-HW, i.e. 7/10, 7 groups of 10 lens

and according to Ernest measurement, Ethos 17mm and 13mm are of the same lens/group layout, i.e. 9 lens in 5 groups

How do you copy a 5/9 to 7/10 design?

2. Patent: There's loads of patents about eyepiece design if you do a google search, patent is meant to protect intelletual properties, it is surely not perfect(what else is?), but it's the norm at present. Taking out patent or not is up to each inventor's own desicison, but I can't see the logic acusing other's copying when there's no patent. Meade/Televue dispute was something settled in US court, if I recall correctly-

3. Concept of ultra wide eyepiece is not totally new, there's this 120° Koehler in 1960!

http://www.quadibloc.com/science/opt04.htm

3. The progress of ultra wide eyepiece is not solely the result of ingenious optical design, the progress of lens coating has much to do with it, here's a link to some reflections:

http://www.canonrumors.com/tech-articles/all-about-lens-coatings/

a relevent quote from the page if you don't have time to read through it:

"If you’ve read any of my “History of Lens Development” articles you may have noticed the early lenses usually had just a few (4 to 6) elements. This wasn’t because the early designers weren’t capable of calculating more complex designs, or the lensmakers of building them. It was because every lens element (other than those cemented together) reduced the amount of light transmitted through the lens by 4 to 8%, the rest was scattered by reflection. The reflected light caused flare, ghosting, and reduced contrast in the image."

A simple calculation makes it easier to understand why Koelher design is not more widely known(besides the cost at the time): asuming 6% light loss of each surface (94% transmission), 14 surfaces of this eyepiece will have (0.94)^^14=42%, nowadays good coatings reach 99% to 99.5%, which essentially make multi-lens (>=10 lens surfaces) practically no visible transmission loss.

 

[JOC]

Well, I can't do a comparison, but courtesy of faulksy's broken clutch and finally the post office today I am the proud owner of a 5mm Pentax XW.  My word, what a stonking object!  I thought my lovely 14mm Baader Morpheus was a large object, but this XW is just as large if not larger.  I am def. going to be tempted to put it in the 2" focus holder.  I haven't tried an EP in there yet and don't know what difference, if any, that it might give as it has the 1.25" fitting which must itself limit the view to that width.  I've got 2"/1.25" dual EP's but just haven't tried it.  Given all the good views I've read about these Pentax XW's I have high hopes and now need a clear night to try it - I should get 240X out of it (need a very clear night methinks!).  Maybe when I do I will report back.

[John]

11 minutes ago, JOC said:

Well, I can't do a comparison, but courtesy of faulksy's broken clutch and finally the post office today I am the proud owner of a 5mm Pentax XW.  My word, what a stonking object!  I thought my lovely 14mm Baader Morpheus was a large object, but this XW is just as large if not larger.  I am def. going to be tempted to put it in the 2" focus holder.  I haven't tried an EP in there yet and don't know what difference, if any, that it might give as it has the 1.25" fitting which must itself limit the view to that width.  I've got 2"/1.25" dual EP's but just haven't tried it.  Given all the good views I've read about these Pentax XW's I have high hopes and now need a clear night to try it - I should get 240X out of it (need a very clear night methinks!).  Maybe when I do I will report back.

I love the XW's. They do fine in either a 1.25" focuser or in a 2" with an adapter. They are designed to be used as 1.25" eyepieces (apart from the 30mm and 40mm of course).

 

[Louis D]

16 minutes ago, JOC said:

My word, what a stonking object!  I thought my lovely 14mm Baader Morpheus was a large object, but this XW is just as large if not larger.

Pick up a 3.5mm Pentax XW.  I thought my 5.2mm Pentax XL was long until I got the 3.5mm XW.  Of course, just about any of the Speers-Waler eyepieces were very long as well.

[Louis D]

3 hours ago, YKSE said:

1. Nikon NAV-HW:

This is the lens/groups about Nikon NAV-HW, i.e. 7/10, 7 groups of 10 lens

Can you provide a link to the Nikon patent on their NAV-HW line?  That way, we can compare their diagrams for similarities to the supposed Ethos design shown above.

[YKSE]

There's no Nikon patent for their NAV-HW, but they do specify their lens/group, which Televue doesn't do.

[F15Rules]

29 minutes ago, John said:

I love the XW's. They do fine in either a 1.25" focuser or in a 2" with an adapter. They are designed to be used as 1.25" eyepieces (apart from the 30mm and 40mm of course).

 

The XWs are ergonomically very good, but I must admit I prefer the shorter ones from 7mm down. Unlike the Morpheus they can't be used straight into a 2" diagonal or focuser - you need an adapter to 1-25".

I always use my 1.25" eyepieces in a Baader Clicklock adapter (2" to 1.25") and they are then rock solid☺.

Enjoy your 5mm, it's a wonderful eyepiece.

Dave

[JOC]

Ah, well if it's designed to be 1.25" then this is what it shall be.  I just looked at the double structure on it and assumed it would be be compatible with the 2" too.  1.25" suits me fine as it's what I tend to use as I noted above.  Thanks for the clarification :-D

[F15Rules]

The Vixen LVWs are the same?..

Dave

[25585]

9 hours ago, Saganite said:

I have a pair of 24mm Pans, as you know, and they are superb in a binoviewer, and that form of observing, I am dedicated to, but the ES 24 68 deg gave very little to the Pan 24, and I would have gladly used them had I been able to do so, and certainly the cost saving would have been very worthwhile. 

Eye relief is better (on paper) for the ES24 68 deg if I remember. So probably that or the Orion Lanthanum 20mm will be my choice. 

I see there is a 22mm Nagler on ebay, shame about the eye relief on that model...

I need to get selling redundant eps really...

[John]

18 minutes ago, 25585 said:

I see there is a 22mm Nagler on ebay, shame about the eye relief on that model.....

 

I've kind of lost track of all the discussion on eye relief lately but whats wrong with the 22mm Nagler ?

I really liked the one that I had - very comfortable to use and top optical quality. But then I don't wear glasses when observing.

Note: this is not the topic of this thread though so perhaps we should discuss somewhere else ?

[25585]

2 minutes ago, John said:

I've kind of lost track of all the discussion on eye relief lately but whats wrong with the 22mm Nagler ?

I really liked the one that I had - very comfortable to use and top optical quality. But then I don't wear glasses when observing.

Note: this is not the topic of this thread though so perhaps we should discuss somewhere else ?

My bad maybe. The 22mm LVW is my quarry & in browsing the bay, noticed the Nagler. Looked it up & er is less than the T4. 

Pentax XW, Vixen LVW & the ES24 68 Ar all have almost or exactly 20mm ER. More is better...

I would like to try the Delos range. Maybe SGL party next year. 

[25585]

3 hours ago, Louis D said:

Pick up a 3.5mm Pentax XW.  I thought my 5.2mm Pentax XL was long until I got the 3.5mm XW.  Of course, just about any of the Speers-Waler eyepieces were very long as well.

If you go to telescope.com the Orion US site, they have the whole LHD range. The 3 shorter FL eps are very tall looking, 14 & 20mm more cylindrical. 

[Louis D]

12 hours ago, F15Rules said:

Why not try the ES 24mm 68?

Because it has no where close to 20mm of usable eye relief (12mm as measured by Bill Paolini).  25585 needs long eye relief eyepieces as do I.  The 27mm Panoptic is short on eye relief as well at a measured 14mm of usable ER.

[25585]

14 minutes ago, Louis D said:

Because it has no where close to 20mm of usable eye relief (12mm as measured by Bill Paolini).  25585 needs long eye relief eyepieces as do I.  The 27mm Panoptic is short on eye relief as well at a measured 14mm of usable ER.

My best TV is 35mm Panoptic. It has good enough eye relief & AFOV. So a 20 to 25 with same and minimum eye relief of 20mm is what I am after. 

Orion Lathanum LHD or Pentax XW cost almost the same, both have advertised 20mm er.

[GavStar]

As the OP, this thread prompted me to have a go with my 22mm vixen lvw this evening. It's very nice but in my opinion the ES 92 17mm is better in all aspects (apart from size and weight ?). The ES has slightly more fov, more comfortable for me and better corrected to the edge in my f6.3 frac, with whiter presentation. A great eyepiece that wasn't available when I originally posted.

[25585]

14 minutes ago, GavStar said:

As the OP, this thread prompted me to have a go with my 22mm vixen lvw this evening. It's very nice but in my opinion the ES 92 17mm is better in all aspects (apart from size and weight ?). The ES has slightly more fov, more comfortable for me and better corrected to the edge in my f6.3 frac, with whiter presentation. A great eyepiece that wasn't available when I originally posted.

That 17mm is the EP 2nd on my list had I not been able to buy a Nikon SW 17.5. They each cost about the same!

[Louis D]

9 hours ago, John said:

10 hours ago, 25585 said:

 

I've kind of lost track of all the discussion on eye relief lately but whats wrong with the 22mm Nagler ?

I have the 17mm and 12mm T4s, and have tried several samples of the 22mm T4 at star parties, and all are very tight on eye relief when used with eyeglasses to see all 82 degrees.  That, and there is some field curvature and edge aberrations, though slight.  I'm seriously hoping ES makes a 22mm to 24mm ES-92 eyepiece.  It will probably be super huge, though.