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Eyepiece experts.....do you know?

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#1 Scanning4Comets

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Posted 17 August 2014 - 02:08 PM

Been going through a little bit of a debate with two observing friends.

 

They say that TeleVue NJ Plossls have a sharper view AND better transmission than the TeleVue Delos eyepieces....

 

I'm leaning towards the Delos....

 

What are your thoughts? Have any of you done extensive tests to know for sure? :question:

 

Cheers!


Edited by Scanning4Comets, 17 August 2014 - 03:19 PM.


#2 howard929

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Posted 17 August 2014 - 02:25 PM

If you're happy with Delos, shouldn't that be fine enough for you? No one is going to be able to confirm your personal preference to you. Or convince your friends that they'e wrong about what they like.

 

(slow going Sunday guy?) No Football!!


Edited by howard929, 17 August 2014 - 02:28 PM.


#3 Scanning4Comets

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Posted 17 August 2014 - 02:53 PM

We are just curious, nothing more. We were all having a nice "adult debate".

 

So, I have made this post to find out.

 

Sorry, I don't watch sports, "guy."

 

Cheers,


Edited by Scanning4Comets, 17 August 2014 - 03:04 PM.

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#4 PJ Anway

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Posted 17 August 2014 - 03:14 PM

Don't know about the "expert" thing, but I have had several TV "circle NJ" plossls in the past and felt they were excellent contrast eyepieces. At present I own a nagler 7mm T1 "circle NJ" and it is in my "never sell" group, an outstanding eyepiece. Having a full set of Nikon 72° widefields, I haven't tried a TV Delos.



#5 tomjones

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Posted 17 August 2014 - 03:37 PM

Way back in January 2013 noticed that the 2nd (little) red spot was preceeding the Great Red Spot by 1/4 of planet rotation and would be centered on Jupiters disk shortly after sunset, with the GRS on the planet edge coming around.  My 10" newt should be perfect for this.

 

Got all set up with my plossls and orthos in their giant case.  Hummm.....no little red spot, but could see the Greater one coming around the edge.

 

Had about 40 eyepieces and tried everything under 10mm and nothing, no Brandon or Zeiss, but most everything you ever heard of.

 

The Delos had just come out with a 6mm, so went in to grab that.  And what do you know, there was the little red spot centered on Jupiter,

even with a little red tint to it!  Totally invisible with common Or's & Pl's. 

 

Little eyepieces with minimal elements stopped being my favorites after that and I just use Pentax XW's, Delos, and E.S. 68's for low powers.



#6 PJ Anway

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Posted 17 August 2014 - 04:15 PM

By the way, has anyone been able to determine what the "circle NJ" stands for. I wonder if it means Tele Vue had them made in New Jersey.  :grin: 



#7 SteveG

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Posted 17 August 2014 - 04:16 PM

Or the scope equalized thermally, or seeing improved, etc.

It takes weeks of back and forth testing to determine real differences.

 

I've compared many eyepieces over the years, and it's rare to get consistent results, which can be very subjective.

 

For planetary, I've found that my Brandon's are slightly better than my Pentax XW's for showing low contrast details.

 

YMMV


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#8 csrlice12

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Posted 17 August 2014 - 04:50 PM

NJ: Not Junk :lol:



#9 Scanning4Comets

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Posted 17 August 2014 - 04:52 PM

I'm looking more for transmission, (faint stuff would be a good test for that), between both and overall sharpness in different scopes.

 

I guess we will just have to have our own shootouts over time until the winter comes along to determine which one wins in each department.

 

Cheers and thanks for your thoughts....

 

Should be a fun time! :jump:

 

LET THE GAMES BEGIN !!!!! :)


Edited by Scanning4Comets, 17 August 2014 - 04:56 PM.


#10 Starman1

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Posted 17 August 2014 - 05:16 PM

Actual wavefront error measurements on the Ciel et Espace website show the Delos wavefront to be accurate enough

no human could see the error introduced, so sharpness isn't going to be a difference.

Transmission of the CURRENT Plossls may be a point or two higher, but that's not going to be visible either.

And the TeleVue Plossls of that era didn't have the high level of tranmsission they have today.

Of course, try using an 8mm Plossl and compare its ease of use to an 8mm Delos, and there's no comparison.

 

Circle NJ refers to a particular manufacturer in Japan that TeleVue won't reveal.

They were not the only eyepieces with that designation as some Celestron Silver Top Plossls also bore the same mark.



#11 jetstream

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Posted 17 August 2014 - 05:45 PM

Markus,I am no expert on eyepieces but there are a lot of good reports out there to help guide us,written by experienced observers with great equipment and good skies.I take this author to be one of them http://www.faintfuzz...m/AboutUs2.html .As is said the Delos ranks highest among widefields in real world transmission tests using threshold objects and is bested by the Zeiss Abbe.It is interesting to note the graph that shows how aperture effects the perceived difference in object detection when comparing eyepieces.The Delos goes deeper than the Ethos in big scopes,under great conditions and the Ethos is very good.

 

As Don has said the TV plossl's back then didn't have the transmission of current EP's. The Delos is reputed  to have some of the best coatings and glass out there in comparison.

 

As far as sharpness.....lots depends on the type of scope used I think...... :shrug:


Edited by jetstream, 17 August 2014 - 06:04 PM.


#12 GeneT

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Posted 17 August 2014 - 06:37 PM

To see throughput differences between the Delos and TeleVue Plossl eyepieces, you would need to view from some truly dark skies. The small glass and fewer lens Plossls should have a slight advantage. However, you would have to do some A B comparisons between the two series to answer this for yourself. The Delos would be much more comfortable an eyepiece to look through, especially when moving into the short focal length eyepieces. The Delos and Ethos eyepieces are among the best all around performers that one can buy. I believe you will find the throughput from a Delos vs. a Plossl to be almost indistinguishable. However, the 72 AFOV  and a larger eye lens will make the viewing experience much more enjoyable.    



#13 jrbarnett

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Posted 17 August 2014 - 06:40 PM

Been going through a little bit of a debate with two observing friends.

 

They say that TeleVue NJ Plossls have a sharper view AND better transmission than the TeleVue Delos eyepieces....

 

I'm leaning towards the Delos....

 

What are your thoughts? Have any of you done extensive tests to know for sure? :question:

 

Cheers!

Almost certainly they are correct.  Even the current crop of 20mm Televue Plossls have outstanding transmission; on the order of 98.88% peak transmission at 598nm.  Figure the Delos has at least two more surfaces than the Plossl so even if the coatings differed by 0.25% per surface, the extra two surfaces would negate the coating advantage.

 

Sharper?  Tell them to have their eyes checked!  :lol:  Plossls aren't even the sharpest on-axis designs among simple eyepieces.  They are quite beatable in the sharpness department.

 

- Jim 


Edited by jrbarnett, 17 August 2014 - 06:41 PM.

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#14 GlennLeDrew

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Posted 17 August 2014 - 06:44 PM

Many eyepieces will differ in transmission by less than 10%. I challenge anyone to consistently perceive such a difference in blind tests. Any comparisons performed where the tester knows which eyepiece is being looked through are highly suspect.

 

One easy way to do such comparisons objectively is to photograph any two eyepieces held side by side while pointing them toward an evenly illuminated white screen. Focal lengths can differ wildly; etendue ensures surface brightness is preserved, with any differences resulting from transmission differences. Ensure that the two eyepiece views about equally straddle the field center, and stop the taking lens down at least somewhat, so as to minimize gradients arising from vignetting. Measure the pixel brightness of a group numbering enough to well average out noise.

 

Relying on the eye to do such comparisons--especially where visual memory is involved during sequential viewing--is too insensitive due to the visual system's huge dynamic range.


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#15 csrlice12

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Posted 18 August 2014 - 12:20 AM

Maybe instead of better eyepieces,what we really need is better eyes.....We are the weakest link.........


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#16 gder01

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Posted 18 August 2014 - 02:21 AM

I have been wondering the exact same thing. My clearest views are through a 13mm circle R I have right now. It is my best eyepiece at the moment. Everything pops out at me when I look through it. The view is a bit narrow and the ER is right at the comfort threshold. I am afraid of "upgrading" to wider afov eyepieces that have less transmission, sharpness or contrast. I don't have much aperture to work with (80mm), and so I need everything I can get when looking at DSOs.



#17 planet earth

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Posted 18 August 2014 - 04:19 AM

Maybe instead of better eyepieces,what we really need is better eyes.....We are the weakest link.........

I'll settle for younger eyes and I'll never eat another Big Mac. :)

 

http://health.howstu...erol-levels.htm

 

Sam



#18 Sarkikos

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Posted 18 August 2014 - 05:56 AM

I have gone deeper with Sterling Plossls than with XW's or Brandons. IIRC, Alan of Faintfuzzies said that Delos have better light transmission than XW's or Ethos, according to his field tests.  Unfortunately, I didn't test the Sterlings against TV Plossls before I sold all my TV Plossls, and I haven't tested the Sterlings against Delos.  

 

You know the Sterlings have excellent light transmission. If I were you, for bagging the dimmest objects, I'd stick with the Sterlings and Delos.  I don't think I'll revisit the TV Plossls.  But I'd be curious to hear the results of anyone who has compared TV Plossls directly against Delos. They should keep in mind that this concerns light transmission and visibility of dim objects, not contrast or ability to see fine planet surface detail.  I would put more credence in actual field tests at night rather than bench tests during the day, though the latter should not be rejected out of hand.

 

:grin:

Mike


Edited by Sarkikos, 18 August 2014 - 06:08 AM.


#19 Don Taylor

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Posted 18 August 2014 - 07:39 AM

Interesting thread - and I did a small eyepiece comparison two days ago which yielded some suprised. While in no way was it a thorough and extended comparison as Bill P would do - there were a few suprises.

I compared the 14 mm ES82, 13mm Nagler T6, 13mm TV Plossl smooth side (1982 vintage), BST FF 12mm, and a recently purchased GSO 12 mm Plossl. I used the ETX 90 mounted on the Porta II.

Wi though getting into the details too much - the TV Plossl and the BST were quite noticeably dinner and slightly lower contrast. In fact the TV Plossl seemed slightly muddy in contrast, brightness, and tone compared to the others save the BST which was similar. The brightest and highest contrast image was actually with the GSO - bought last week for $23. (Branded as Astro tech from our sponsor).

All eyepieces were carefully cleaned - except the GSO which was new. Obviously there are FL differences here and as I said not a thorough review - and no Delos to compare.

The message to me was that coating technologies have greatly improved since the TVPlossl was made in the early 80s and the inexpensive eyepiece showed a brighter image. The complex 82 degree eyepieces were better too in spite of the increased number of elements.

Repeated the test with 9T6 Nagler, 8.8 ES82, 8mm TV Plossl (2000 vintage) GSO 9mm Plossl, and BST FF 8mm with similar results. Makes me think TV did not improve the Plossl coatings by the time that EP was built - I bought from stock at a local dealer about 2000 but it could have been there a while.

I 'd like to compare to recent manufacture TV Plossls (and Delos too).

#20 BillP

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Posted 18 August 2014 - 07:55 AM

I did some compares of the current gen 11mm Plossl and NJ 13mm against the T6s, and the Plossls were noticably sharper on-axis with a crisper more defined view.  Never did any compare with the Delos though so can't say.



#21 Sarkikos

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Posted 18 August 2014 - 08:56 AM

I keep a T6 2.5 and a T5 31.  The 2.5 is for a wide field view of structure in planetaries, galaxies and bright nebula, especially when the mount does not track.  Dark adapted eyes have diminished visual acuity, so they need a power boost. This is similar to someone with presbyopia using "cheater" glasses to read fine print.  The 31 is for wide field views of large DSO and star fields.  

 

But I don't depend on either of them to bag the faintest of the fuzzies. For the really dim stuff I use Sterlings or Delos, or maybe try to dial in the best exit pupil for the specific object with one of my zooms.

 

Mike


Edited by Sarkikos, 18 August 2014 - 09:01 AM.


#22 cpper

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Posted 18 August 2014 - 09:18 AM

Interesting thread - and I did a small eyepiece comparison two days ago which yielded some suprised. While in no way was it a thorough and extended comparison as Bill P would do - there were a few suprises.

I compared the 14 mm ES82, 13mm Nagler T6, 13mm TV Plossl smooth side (1982 vintage), BST FF 12mm, and a recently purchased GSO 12 mm Plossl. I used the ETX 90 mounted on the Porta II.

Wi though getting into the details too much - the TV Plossl and the BST were quite noticeably dinner and slightly lower contrast. In fact the TV Plossl seemed slightly muddy in contrast, brightness, and tone compared to the others save the BST which was similar. The brightest and highest contrast image was actually with the GSO - bought last week for $23. (Branded as Astro tech from our sponsor).

All eyepieces were carefully cleaned - except the GSO which was new. Obviously there are FL differences here and as I said not a thorough review - and no Delos to compare.

The message to me was that coating technologies have greatly improved since the TVPlossl was made in the early 80s and the inexpensive eyepiece showed a brighter image. The complex 82 degree eyepieces were better too in spite of the increased number of elements.

Repeated the test with 9T6 Nagler, 8.8 ES82, 8mm TV Plossl (2000 vintage) GSO 9mm Plossl, and BST FF 8mm with similar results. Makes me think TV did not improve the Plossl coatings by the time that EP was built - I bought from stock at a local dealer about 2000 but it could have been there a while.

I 'd like to compare to recent manufacture TV Plossls (and Delos too).

 

 

Don, how did the ES 14mm 82° compare to the 13mm Nagler ?


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#23 howard929

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Posted 18 August 2014 - 09:18 AM

Interesting thread - and I did a small eyepiece comparison two days ago which yielded some suprised. While in no way was it a thorough and extended comparison as Bill P would do - there were a few suprises.

I compared the 14 mm ES82, 13mm Nagler T6, 13mm TV Plossl smooth side (1982 vintage), BST FF 12mm, and a recently purchased GSO 12 mm Plossl. I used the ETX 90 mounted on the Porta II.

Wi though getting into the details too much - the TV Plossl and the BST were quite noticeably dinner and slightly lower contrast. In fact the TV Plossl seemed slightly muddy in contrast, brightness, and tone compared to the others save the BST which was similar. The brightest and highest contrast image was actually with the GSO - bought last week for $23. (Branded as Astro tech from our sponsor).

All eyepieces were carefully cleaned - except the GSO which was new. Obviously there are FL differences here and as I said not a thorough review - and no Delos to compare.

The message to me was that coating technologies have greatly improved since the TVPlossl was made in the early 80s and the inexpensive eyepiece showed a brighter image. The complex 82 degree eyepieces were better too in spite of the increased number of elements.

Repeated the test with 9T6 Nagler, 8.8 ES82, 8mm TV Plossl (2000 vintage) GSO 9mm Plossl, and BST FF 8mm with similar results. Makes me think TV did not improve the Plossl coatings by the time that EP was built - I bought from stock at a local dealer about 2000 but it could have been there a while.

I 'd like to compare to recent manufacture TV Plossls (and Delos too).

If the difference between old coatings on old eyepieces vs new w/new is very noticeable then the idea of  "life time" eyepieces falls a bit short. Possibly this is why 10 people report 12 opinions on what "seems" to be the same eyepiece.

 

Some questions. anyone have a first gen T6 and compared it to a brand new one of the same focal length? Does TV update coatings on all of their eyepiece lines? Do any of them do that? Last. Is the coatings on a Delos the same as on new T6's? I asked about TV only because there's so many of them out there and so many of YOU own them.


Edited by howard929, 18 August 2014 - 09:54 AM.


#24 Starman1

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Posted 18 August 2014 - 10:10 AM

The T6s are of Japanese manufacture, and use different glass types internally than the Taiwan-made Delos.

Ergo, the coatings will be of differing materials due to differences in glass types and country of origin.



#25 howard929

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Posted 18 August 2014 - 11:10 AM

The T6s are of Japanese manufacture, and use different glass types internally than the Taiwan-made Delos.

Ergo, the coatings will be of differing materials due to differences in glass types and country of origin.

Don,

 

Again please. I asked about TV because there's so many of their EP's out there and of varying ages and possibly with different coatings on what might seem to be the same eyepiece? OTOH if Taiwan and Japan can't or won't share coating technologies then I'm left wondering what TV is or isn't doing in regards to writing specs for their new eyepieces. Anyway, i'm wondering more about any possible viewing differences between eyepieces with older coatings vs brand new on the same eyepieces from any manufacturer. 








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