22 replies to this topic

[thecelloronin]

Hello all,

 

I'm looking to get into green-lettered eyepieces, namely the 22T4. My instinct is to buy used and save money, but I've also read that new stock will always have the latest and greatest coatings.

 

Given that the 22T4 is an older model, would buying new stock yield > $100-worth of (Edit: Good point, havasman!) a noticeable improvement on the coatings? 

Edited by thecelloronin, 24 January 2021 - 10:24 PM.

[havasman]

"$100-worth" is a variable not a constant. $100 to a guy with a jet, 3 homes, thousands of acres and lots of dough is a different thing than it is to the rest of us.

You have to make that call yourself.

But the older T4 Naglers had great reputations too.

[wrvond]

No.

 

Tele Vue will make changes during the production run without any kind of announcement or indication a change has been made, but as long as the coatings are undamaged you won’t be able to tell the difference. Compare two eyepieces side by side and you won’t be able to tell which is the older of the two just by coating color.

[jimandlaura26]

It’s a great eyepiece... no matter when it was made...

Edited by jimandlaura26, 24 January 2021 - 10:36 PM.

[BillP]

I'm looking to get into green-lettered eyepieces, namely the 22T4. My instinct is to buy used and save money, but I've also read that new stock will always have the latest and greatest coatings.

 

Given that the 22T4 is an older model, would buying new stock yield a noticeable improvement on the coatings? 

 

Interesting question.  First of all it is IMO natural for companies to always provide the latest in coatings.  Why?  Because the optical coating companies need to stay competitive so they naturally use the newest approaches and discard the old so they can maintain market positioning and business.

 

Since all eyepieces are different, let's look specifically at the 22T4.  That eyepiece is 7 elements in 5 groups according to Tele Vue and was first offered in 1998 so an oldest used one could be almost 23 years old!  Given this eyepiece has 5 groups, which means 10 air-glass interfaces, if you got an old one from 1998 used and presuming coatings of that vintage might be at least a half of a % less efficient, overall it would mean that the old 22T4 could have a total transmission of 5% less than a new one.  If there were a 1% difference in coating efficiencies from 23 years ago, then the total transmission could be as much as 9% less than today's coatings.  In either case, even a 5% difference is a rather lot IMO.  Yes you will hear folks talk about how most experienced variable star observers cannot reliably see less than a 10% difference, but let's remember that we are not talking about so much seeing transmission differences for bright point sources, but more likely faint extensions of galaxies and nebula, in which circumstance I am sure the eye is much more sensitive based on just how differently these faint objects appear in varying same-model year eyepieces -- I am thinking of Amilia's excellent review on 12 XF vs. 12 Radian vs. 12 Pentax SMC Ortho where the brightness of a galaxy was quite a bit difference between the 3 eyepieces all of which were probably a lot closer in transmission; and I am also thinking how some of today's premier DSO amateurs with their large Dobs notice the difference in detecting faintest DSO in say an Ethos vs. Delos vs. ZAO.  So IMO, if you are concerned about having the brightest possible view to catch faint galaxies through your particular scope, then if it were me I would get the new one.  However, my passion is not faint fuzzy hunting so I myself would get an older one and pocket the savings never looking back.   If however you find a used one where the seller has their sales receipt and can confirm it is less than 5 years old, I think it would be fine to get that vs. new.
 

See Pic #14 a little more than half way down - https://www.cloudyni...pentax-xf-r1393

Edited by BillP, 24 January 2021 - 10:55 PM.

[f74265a]

Dirt and wear and tear from cleaning or abuse could impact a used model as much or more than older coatings. Personally, I strongly prefer new.

[siriusandthepup]

I think you might be stressing yourself and over-emphasizing the importance of acquiring the "latest and greatest".

 

Eyepieces from 20 or 25 years ago still perform excellently.

 

If you are of the nature that you need to live on the bleeding edge - then of course, get a new one.

 

Stone me if you must, but I have no problem using eyepieces without multi coatings. Mag fluoride coatings still work for me.

 

Old, but clean, optics do not offend me.  Still love my 30 year old Brandons and 25 year old Tak LE's and 25 year old TV Naglers and Plossls. I wouldn't pay much at all for the offer for a brand new similar eyepiece just for the possibility of "better coatings". In fact, I like some of the older eyepieces because of their build quality.

 

But, that's just me.

 

good luck!

Edited by siriusandthepup, 24 January 2021 - 11:21 PM.

[markb]

I agree with Havasman, only you can make that cost benefit calculation.

 

TV always had excellent coatings, and TV products were expensive, so they almost always were well cared for.

 

I've had good luck with used TV eyepieces, and am not driven to extract an extra percent of so of throughput.

 

Certain types of observing will call for that extra drop of performance, so only you and your wallet can decide. For me, I have a few other items higher on my list. For now.

 

I have a range of smoothie Naglers and they suit my budget and eyes.

 

If I hit the stock market jackpot I would go for all new NT6 and Ethos without a regret or second thought. Virtually every TV product has made me happy.

 

I will leave it to the retinal sensitivity experts, but it is my understanding that a percent or two of light reduction may not be readily perceptible except under limited circumstances. And I have no doubt certain, limited, observations may call for it.

[sanbai]

There's an easy age difference to spot in the 22T4. Newer models have a tapered undercut. Older models have a straight one.

I bought mine second hand, older version. I had no idea back then of the undercut difference. I'm happy with it.

I may spot such supposed 5% difference ( 0.07 photographic "stops") only in a comparison of gray bands printed side by side on a paper or on a monitor. Not changing eyepieces, especially given lack of both time and sky conditions necessary for that, not to say skills. Also, there are plenty of DSO to be observed above the extreme limits...

Of course, if I win jackpot I would renew all my pre-owned EPs. Even more, as multimillionaire, I would not clean them, just buy new ones and give the old ones away..

[SeattleScott]

I did have an issue with transmission on a vintage T1 Nagler. In side by side comparison with a different eyepiece, it was clearly dim. Not dramatic but quite noticeable. Another T1 Nagler didn’t seem to have this problem. So it might not be the age of the coatings so much as the condition of the coatings.

Scott

Edited by SeattleScott, 25 January 2021 - 12:20 AM.

[TOMDEY]

I measured two vintage and one newer TeleVue eyepieces in the lab. As you can see, the throughput and coatings are improved, but all are superlative. Here are 3 slides from my 32-page white-paper on the topic, "Photometric Throughput of Visual-Use Astronomical Telescopes".   Tom

Attached Thumbnails

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[siriusandthepup]

I will say that the 13mm Ethos is on my "acquire list". Nothing against the early 13mm Nagler, the Ethos 13mm is simply a superior design.

 

Don't ever look through one or it will be on your list as well!

[droid]

While there are very experienced observers who might see the difference in old coatings vs newer coatings, a large percentage of amateur astronomers might not even see it.

 

And sometimes older is better, in my opinion

 

I spent nearly a year comparing a 20 type 2 to a Meade UWA 20mm , both 82 degrees

 

in a 4 inch f10, a 6 inch f8 both refractors, and 12 inch f4.9 dob.

 

the 20 type 2 won, the stars were sharper, the back ground was slightly darker, and the looking through a port hole effect was slightly better.

 

Every one is different, so your mileage may vary , 

[Echolight]

While there are very experienced observers who might see the difference in old coatings vs newer coatings, a large percentage of amateur astronomers might not even see it.

 

And sometimes older is better, in my opinion

 

I spent nearly a year comparing a 20 type 2 to a Meade UWA 20mm , both 82 degrees

 

in a 4 inch f10, a 6 inch f8 both refractors, and 12 inch f4.9 dob.

 

the 20 type 2 won, the stars were sharper, the back ground was slightly darker, and the looking through a port hole effect was slightly better.

 

Every one is different, so your mileage may vary , 

I'd guess that it would take an experienced observer to actually have TWO eyepieces of such similar specs but different age to compare.

 

The question that keeps nagging in the back of my mind is, why doesn't the 12 inch dob have a name?

[BillP]

While there are very experienced observers who might see the difference in old coatings vs newer coatings, a large percentage of amateur astronomers might not even see it.

I don't think one has to be very experienced, they just have to know where subtle transmission/contrast differences will show up as more easily discernible.  Then becomes one of those things that once you see it, hard to unsee it with eyepieces

 

FWIW I've had some T1s and by today's standard I felt those were quite dark.  Had 2 with coating failures as well.  Nothing is forever.  A few years back found a set of the old Meade smoothie UWAs that were sealed in original packaging at an estate sale.  I of course opened them, unsealed the plastic wrapper, and put them to some good observing use.  Quite obvious that while these oldies performed well, their brightness was not quite as bright on star points than modern complex eyepieces.  Small improvements in coatings do make a difference when the lens count in an eyepiece is large.

Edited by BillP, 25 January 2021 - 06:25 PM.

[teashea]

Coating technology is improving.  Given the choice, I would choose an eyepiece that has newer coatings.

[25585]

Same with binoculars. I have 50 y/o Zeiss that are bettered by some modern Chinese models!

 

For eyepieces bought pre-owned, depends on previous history & care etc.

[siriusandthepup]

Don't forget that you can offset eyepiece transmission deficiency by purchasing a one-size-larger telescope.

 

Buy all 20 year old eyepieces and then acquire a new one-size-larger telescope with enhanced coatings. Overall - money saved!

 

rofl

Edited by siriusandthepup, 26 January 2021 - 11:06 AM.

[Jeff Morgan]

If your buying minimum glass eyepieces (MgFl) no worries - that technology hasn't changed much since WWII.

 

If you are buying multicoated - probably better to go newer.

 

There are a lot of factors we don't know about as end users. Tele Vue probably does not do coatings in-house, which would make them subject to vendor process and coating changes. Those could be due to improvements in technology, cost and availability of raw materials, or enviro regulations. Or all of them. Likely all of them.

 

If you were buying other brands from major optical houses (e.g., Zeiss, Leica, Pentax, Nikon), those vendors almost certainly coat in-house with better end-to-end control. Maybe even consistency over time, though technology improvements probably occur there too. My guess would be such companies actually make the breakthroughs that eventually trickle down through the industry to third parties some years later.

 

Bottom line is, while newer eyepieces anecdotally and empirically (thanks TomDey!) get better over time, we just don't know what those "cut off" points may be.

[25585]

An example for Zeiss is their T* coatings. With and without show T* made a difference. Of course coatings improve, and moreso recently since ecoglass (lead free) is used by all responsible manufacturers.

[junomike]

Don't forget that you can offset eyepiece transmission deficiency by purchasing a one-size-larger telescope.

 

Buy all 20 year old eyepieces and then acquire a new one-size-larger telescope with enhanced coatings. Overall - money saved!

 

rofl

I do feel this is the best route (one size up) however this might not work for some who's  OTA  is at the acceptable limit. C11 to a C14 or even M12 is a larger jump in weight and possibly another Mount class.

[thecelloronin]

Thanks for everyone’s replies. If I were to average the responses together, the moral of the story is “you really can’t go wrong either way” at least with regards to TV, Pentax, etc.

 

That said, I don’t plan on becoming an eyepiece collector (check back with me in a few years...) In fact I want to build a minimalist kit, so spending a little more to maximize the few EPs I own won’t be a massive financial burden. And hey, I’ve heard from multiple places the 22T4 is a lifetime eyepiece, might as well optimize our starting point together.

[Miranda2525]

I don't think one has to be very experienced, they just have to know where subtle transmission/contrast differences will show up as more easily discernible.  Then becomes one of those things that once you see it, hard to unsee it with eyepieces

 

FWIW I've had some T1s and by today's standard I felt those were quite dark.  Had 2 with coating failures as well.  Nothing is forever.  A few years back found a set of the old Meade smoothie UWAs that were sealed in original packaging at an estate sale.  I of course opened them, unsealed the plastic wrapper, and put them to some good observing use.  Quite obvious that while these oldies performed well, their brightness was not quite as bright on star points than modern complex eyepieces.  Small improvements in coatings do make a difference when the lens count in an eyepiece is large.

...Unless you are old and your eyes are going downhill.