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Tigerider
Vendor (Televue Rep)
Reged: 02/21/06
Posts: 205
Loc: Torrance, CA.
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Quote:
Upon further reflection....
I would imagine that there is significant rectilinear distortion since the angular magnification distortions are negligible. Didn't pick up on that reading viewer's comments on the TV website.
If TV has found a way to correct both angular and rectilinear distortions at the same time, this will indeed be a revolutionary ep.
There was mention of some field curvature in the S&T article.
Kids,
While you cannot simultaneously get rid of both angular magnification and rectilinear distortions,
the rectilinear distortion in the 13 Ethos is less than a 26 mm Nagler Type 5.
--------------------
John Rhodes (TV Rep.)
TeleVue: NP 127is,101is,101
102,85,76,60is,60 all EP's+
Celestron Ultima 11
Celestron C-5
Meade Research Grade 856
Celestron 20 x 80
Canon 20 Da
Canon "is" Binoculars 10x30 & 15x50
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Jim Romanski
sage
Reged: 01/02/05
Posts: 481
Loc: Guilford, Connecticut
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Quote:
Upon further reflection (refraction)....
I would imagine that there is significant rectilinear distortion since the angular magnification distortions are negligible. Didn't pick up on that reading viewer's comments on the TV website.
If TV has found a way to correct both angular and rectilinear distortions at the same time, this will indeed be a revolutionary ep.
There was mention of some field curvature in the S&T article.
Al makes a point of stating that it is corrected for angular magnification and therefore it has rectilinear distortion.
--------------------
Jim
17.5" Dob "Project"
13.1" Coulter
8” Cave
NP 101 on a CG-5
25x100 binos
Naglers, Ethos, etc.
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Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2759
Loc: Just passing through.....
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Well, if the rectilinear distortion is less than my 26N, that ain't bad.
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10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos
Member IDA
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 10960
Loc: Los Angeles
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Quote:
Quote:
Upon further reflection....
I would imagine that there is significant rectilinear distortion since the angular magnification distortions are negligible. Didn't pick up on that reading viewer's comments on the TV website.
If TV has found a way to correct both angular and rectilinear distortions at the same time, this will indeed be a revolutionary ep.
There was mention of some field curvature in the S&T article.
Kids,
While you cannot simultaneously get rid of both angular magnification and rectilinear distortions,
the rectilinear distortion in the 13 Ethos is less than a 26 mm Nagler Type 5.
Because the field is wider, if there is less RD than the 26 Nagler, there is a LOT more AMD. I didn't see a lot of AMD in the sample I viewed. I did see edge-of-field astigmatism. But, because the field curvature of a refractor is opposite in sign to a reflector, I'll reserve judgment until I borrow one.
What I saw did not make me want to buy one immediately. I probably will buy one eventually, but only if it shows better edge correction than the sample I saw.
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Don Pensack
12.5" Truss Dob, 5" Maksutov
Sustaining Lifetime IDA member, TeleVue junkie
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Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2759
Loc: Just passing through.....
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After all this hype, I'm expecting a lot.....
$620 worth..... 
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10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos
Member IDA
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Mike Hosea
Post Laureate
Reged: 09/24/03
Posts: 3229
Loc: "Metrowest" Boston
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Quote:
Because the field is wider, if there is less RD than the 26 Nagler, there is a LOT more AMD.
No, the mutual exclusivity of eliminating one or the other only comes into play as the design approaches perfection (in terms of distortion), and only then can one presume that a decrease in one form of distortion must be associated an increase in the other. The most likely explanation, given that we can easily judge the average angular magnification distortion from the effective field stop diameter, is that the 26T5 does not attain an optimal balance of distortion, i.e. it is most likely possible to design an eyepiece that has less of both kinds of distortion than the 26T5 has.
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Mike
- 7" f/6.7 home-built planetary Newt
- 35mm Panoptic
- 13mm Ethos
- 5mm Tak LE
- 2x TV Barlow
- Canon 10x30IS Binoculars
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Jim Romanski
sage
Reged: 01/02/05
Posts: 481
Loc: Guilford, Connecticut
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Go to the bottom of this web page:
http://www.televue.com/engine/page.asp?ID=311
Where Televue notes:
With zero angular magnification distortion, straight lines on a focal plane appear curved in a pincushion fashion, with the curvature becoming greater the farther they lie from the center. It is impossible to correct an eyepiece simultaneously for rectilinear and angular magnification distortion.”
Al Nagler notes:
For reference, the maximum angular magnification distortion of the new 13mm Ethos is no more than 1% at any point in the 100% field
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Jim
17.5" Dob "Project"
13.1" Coulter
8” Cave
NP 101 on a CG-5
25x100 binos
Naglers, Ethos, etc.
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Lawrence Sayre
Post Laureate
Reged: 10/16/04
Posts: 3704
Loc: N.E. Ohio
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Since the Ethos must therefore be loaded with rectilinear magnification distortion, how does this distortion manifest itself to the viewer (I.E. what does it look like?)?
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My philosophy, in essence, is the concept of man as a moral being, with his own happiness as the moral purpose of his life, with productive achievement as his noblest activity, and reason as his only absolute.
Ayn Rand (in the appendix to 'Atlas Shrugged')
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Dave Mitsky
Postmaster
Reged: 04/08/02
Posts: 6287
Loc: Pennsylvania, USA
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Quote:
Quote:
The vendors I've talked with privately and the one who has posted publicly about it say they've never had a waiting list like this for any eyepiece and despite all the woofing and tweeting about the price there have been almost no dropouts.
I've seen other posts that indicate there has been quite a large number of dropouts. But the only one I know about for sure is me... 
I've also seen a number of posts here and there indicating that some people have indeed bailed on the Ethos.
Dave Mitsky
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Chance favors the prepared mind.
De gustibus non est disputandum.
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Moggi1964
Carpal Tunnel
Reged: 11/07/05
Posts: 2512
Loc: Madison. NJ. USA
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If I had the money to hand I would buy it now. Yes it's a lotta cash and yes I gulped when I saw the price but it is what it is.
Although I am pretty new to the field I figure Al Nagler and his team know what they are doing.
I bet I own one within a year (hopefully used from someone who just couldn't get to like it).
--------------------
Morris
WO Megrez 80 ED F/7
WO 8x42 binoculars
Seymor Rosin F/4.5 Astrograph in the making
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jack45
Carpal Tunnel
Reged: 07/07/03
Posts: 2060
Loc: Lacey WA
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One thing about buying the 13mm Ethos. You may have to change your ep setup. It looks like three would be just about right! That's is the 31mm T/5,22mm T/4 or 20mm T/2 and the 13mm Ethos. These three as I see it will get you a real good viewing night! If seeing is good then maybe add a 10mm or 7mm Pentax XW. With a paracorr and 2x barlow you can't lose! I'm looking at the below listed eps later on maybe!
31mm T/5
20mm T/2
13mm Ethos
10mm Pentax XW
7mm Pentax XW
That's looks like a great setup for me!
Clear Skies!
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16"f/4.5 Discovery Split Tube/TV Paracorr
12.5"f/5 Discovery PDHQ/TV Barlow
Orion SkyQuest f/4.9 XT12"Intelliscope
Orion 120mm F/8.3 Refractor
Burgess BV 24mm aperture/Siebert 4 pc OCA
BV Pairs:26mm,20mm,17mm,14mm,12.5mm
Tele Vue Smooth Side Plossl,10.5mm,13mm,21mm,26mm,TV 11mm
UO Abbe Set,40mm 5000s Plossl,31mm Axiom LX,26mm T/5,LX,23mm Axiom LX,20mm T/2,16mm T/2,15mm Panoptic,14mm Meade UWA,10mm Axiom LX!
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jsiska
super member
Reged: 07/12/06
Posts: 145
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I never purchased a Televue Nagler 31mm Type 5. After I saw this comparative review:
http://www.astromart.com/articles/article.asp?article_id=564
With the recommendation at the bottom of the same review:
"Now all that being said, if I had to choose ONE eyepiece, and ONE eyepiece alone, I’d personally choose the UO 32mm Mk-80. What????? What????? Why????..."
I decided to purchase a University Optics 32mm MK-80.
I am glad that I did. The MK-80 works very nicely with my telescopes.
I agree the 13mm Ethos offers a sweet spot for use with my telescopes; however, with the following review in mind:
http://www.cloudynights.com/item.php?item_id=303
I suspect that I wont have to wait too long before someone will market an ocular for $499 or less that has performance very similar to 13mm Ethos. That said, I too would have ordered a 13mm Ethos if it was marketed for $499.
Jim
----------------------------
GPDX-C102F with Moonlite Motorized focuser, half piller & wood tripod, Vixon SS2K-PC ver 2.06, SBIG STV Deluxe + E Finder + Borg Helical focuser all on a set of JMI Wheeley Bars.
Meade 880, 8” f/6 Research Series Reflector with upgraded thrust bearings, U.O. 80mm finder, Meade 80mm f/15 model 300 guide scope, SBIG ST-4, JMI MotorTrack 5, JMI SGT-MAX & JMI Motorfoucs, JMI EZAlign Polar Alignment scope.
Meade 10" f/4.5 Starfinder dob with 60mm Orion finder & telrad.
1962 60mm, f/11.7 Tasco 9TE with custom visual back remounted on a GEM.
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Craig L
sage
Reged: 05/10/03
Posts: 353
Loc: London, Ontario, Canada
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Cost was a big factor in the review. It should be pointed out that the reviewer said:
"At the end of this review, when the points are totaled up, we find that the 31mm Nagler wins quite handily by accruing the highest points tally. However, we can see that the UO 32mm Mk-80 is a close runner-up. The QX on the other hand is a dismal overall performer and the other two eyepieces do not have to worry about being in any sort of danger from this eyepiece."
Depending on the focal ratio of your scope and your budget, your mileage may vary, as they say.
- Craig
--------------------
7x50, 20x80
Maxscope 40
90mm f13.8 ETX
102mm f8 AP APO
13.1" f4.5 Dob
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ckwastro
professor emeritus
Reged: 11/23/05
Posts: 733
Loc: AZ
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Just got back from vacation and came in late on this. I'd love to have one but I'm going to have to pass on the ETHOS at this price-point. I'm usually right in line for the TV eyepieces, but this focal length is a little different for me as I have 14mm Leica that beat out everything on the block for me personally.
Doing some quick math the ETHOS would give me an additional 1/2 and 1/4 degree TFOV in my two scopes, over my 14mm Leica, which is only 68*. But it's the best 68* I've ever seen as far as sharpness across the field, throughput, and color rendition, and I chose it over the 12 T4, the 13 T6, and the Pentax 14. If I want or need the extra FOV I'll just pop in my venerable 22 T4, which I will never sell, and have a TFOV larger than that of the ETHOS. True, the mag will be less, but I can't justify an additional $320 over the original Leica cost for only a 1/4 degree true field increase in my most used scope, especially when the Leica's optical performance is already outstanding. Maybe a used one someday, but for $620 new, it's sort of diminishing returns for me.
Anyway, to those who do get one, I'm sure it will be a knock-your-socks-off experience. Uncle Al never fails in that department!!
--------------------
Kerry
- 92mm AP Stowaway (f/7 version, uh...actually f/6.57 )
- Takahashi Mewlon 210
- Giro 3 Twin View
- 10x42 Audubon Equinox
- Bogen 3221 tripod / 3047 3-Way Head
- Denk Std BV
Edited by ckwastro (09/11/07 04:05 PM)
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Moggi1964
Carpal Tunnel
Reged: 11/07/05
Posts: 2512
Loc: Madison. NJ. USA
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Quote:
....and look what happened to the sales of the Nagler 13mm...!
I guess Al may be on his way to his second yacht 
(actually i don't think he has a 1st one but you get my drift).
It seems not everyone got "my drift" and interpreted the above as a suggestion that Al Nagler is making a fortune on every EP he sells and that the Ethos is overpriced in order to make him 'even more money'.
Let me make clear what I was trying to say:
The 13mm Nagler that was released in 1980 was a hit with astronomers and as far as I can tell it sold very well.
I was, in my own way, trying to say that I hope this one sells just as well.
It was not my intention to cause offence; when it is my intention it will be abundantly clear 
Thankyou and this is my last post on this topic.
--------------------
Morris
WO Megrez 80 ED F/7
WO 8x42 binoculars
Seymor Rosin F/4.5 Astrograph in the making
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