12.5mm Docter Eyepiece

[FlashDrive]

I have read many ' glowing ' reports about these ....

......has anyone here ' looked ' thru' one.

Docter is an amazing unique ep with some German voodoo thrown in (aspherics??)

http://agenaastro.com/docter-12-5-mm-84-deg-uwa-eyepiece.html

Col......

[dannat]

im not sure if anyone in Oz has one -but i presume there is atleast 1 or 2..reviews on CN put it at one of the best ep's around..some like it better than ethos. im pretty sure John B posted about it a yr or 2 ago -when one of his US visitors dropped it into a focuser for him

you might as well get a leica asph zoom -covers 8.9-17.8mm

[Profiler]

Yep - John B ausastromer reviewed it - basically the best EP he has tried coupled with one of the biggest prices:thumbsup:

[FlashDrive]

According to many owners on CN who have this eyepiece.... it's an absolute keeper ... never to be ' sold ' .... or the ' very last ' eyepiece they would ever part with.

Some even have 2 of these for Bino use.....

http://www.cloudynights.com/topic/469276-docter-uwa-125mm/?hl=docter#entry6118147

Col.....

[Camelopardalis]

In Europe, it's only 50 euros or so more than a 13mm Ethos...

[FlashDrive]

Found this thread on the Docter 12.5mm Eyepiece
Credit to John Bambury....:thanx:

http://www.iceinspace.com.au/forum/showthread.php?t=74054

Col.....

[N1]

Make sure you do a review on here when you get yours Flash :P
I've decided against forking out for it, because a) it's too lumpy, b) I have a 13mm Nagler, which is just what the Docter ordered, and c) it's not a Total Solar Eclipse.

[FlashDrive]

:D ... yeah but by all accounts a very impressive eyepiece... and yes ...one is on its way to me now....got shipping information today from Agena USA.... she's in the post.

Some people may think .. what a waste of money... they would have spent it on other items, let alone a ' single ' eyepiece.....for me it's no different to forking out on any ' high end ' item.

Cost me just under the GST requirement to import it.....only just tho'.

Obviously, this will be my most ' prized ' eyepiece, and will be the first I grab when Scope time is favorable.

Should go well in my TeleVue Genesis SDF Petzval ' Fluorite '

Looking forward to receiving it :D

Col.....

[Kunama]

I think it is a great way to spend money Col and look forward to trying it out at some stage.
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Oh and another thing .......................... Dibs ;):D;) !!!

[N1]

Everybody has different priorities. Do let us know how you are going with yours (when the time comes). Some comparos will also be appreciated I'm sure.

[Camelopardalis]

Don't matter what other people think Col, sounds like a mighty fine piece of glass, look forward to hearing your thoughts on it once its seen some photons :thumbsup:

[FlashDrive]

Now that is going to be difficult for me, as I don't have any focal length eyepieces with the 84* fov .

The only 12.5mm eyepieces I have here are the Celestron Ultima 12.5mm and the Vixen LV12mm ... both very nice eyepieces.... but I'm sure they are not even in the ' race ' .

After I've had good use of it.... maybe I would forward it to a ' trustworthy ' person to deliberate a proper comparison with an alternative ' high end ' eyepiece of similar specs ..... such as the TV Nag' 12mm or TV Nag' 13mm.... both of which are 82* degree fov.... close enough anyway... and possibly a TV Ethos 13mm .. but it is 100* degree fov.....be a good comparison.

Of course...I would want it back ..... :poke: .... :evil2:

Col......

[Kunama]

I would love to compare it with the 13T6, LVW13 just to see how much difference is seen on axis. I think the mere fact that it is made with the typical German attention to detail would be a big attraction.

I wouldn't recommend you loaning it out though........ the temptation to 'lose' it in the mail would be too great !!!!

[FlashDrive]

Yes ... that's a risk to consider alright .... let me know when you may come up this way again.....bring those eyepieces with you....

We'll have an ' eyepiece shootout ' .... :astron:

On another note ....if this eyepiece is a ' jaw dropper ' and is everything and more that it is reported to be .... I will get another for use in my TV Bino's.... let's hope the exchange rate doesn't head too far south...

Col.....

[FlashDrive]

Very encouraging report.....Bino use.

http://www.cloudynights.com/topic/498181-docter-125mm-eyepiece/#entry6554772

extract : from CN posted by Mark

It's fantastic. Probably more than half my viewing is with 2 Docters in a binoviewer, both barlowed and unbarlowed. Yeah in my opinion it's indeed worth it, absolutely a jaw dropping experience. (tec 180, mark V)

extract : from CN posted by Ian

I have only used a pair in the Docter 40x80 binocular but the view is exceptional. I am going to buy a pair to use in my 100mm APM apo binocular. The view is immersive due to the generous eye relief, wide field and large eye lens with very well designed eye cup. Congrats on your new eyepiece. I don't think it will be long before another is heading your way!

and another report from CN posted by Stephan

Another happy Docter 12.5 UWA bino user here. Definitely lifetime keepers! The Docter works phantastic in any bino configuration - just plain 1:1, or focal extended by any Barlow, Powermate or the Baader FFC.

If the focuser of your TV Genesis-SDF can handle the weight of the bino plus a pair of Docters (check up to fully vertical position), do yourself the favour and buy that second Docter.

hmm... I can see myself getting another one ....:D

Col.....

[N1]

Certainly an interesting EP. I suspect Docter's actually conceived this EP for bino use.

I'd love to see a set of Abbe orthos coming from this company, given its heritage. I must visit them next time I'm over there.

[Profiler]

Does anyone know what the ER is for this EP?

When I looked at the spec's on the Agena site it just listed an X

[Kunama]

From a CN post by T Homma the ER is about 20mm

[dannat]

the reported er is reported on some sites as varying around 10mm, but ive seen posts say it is more. the binocular 40x80 specs say er is 10mm [reported to be the same ep]

[Profiler]

I have given this EP a bit of thought in terms of its physical appearance, discernible dimensions and stated specs. When considering it's size in particular with fov (and especially ER if indeed only around 10mm) I feel the optical mechanics of this EP may be closer to a 13mm T1 Nagler than anything else.

However, having said this I want to stress that a German made glass and coatings can make a gigantic difference (as Dr Zeiss will attest) and there is likely to be a no contest between the T1 Nagler and this Docter

[N1]

http://www.docter-germany.de/en/products/prod/cat/observation-spyglass/prod/docter-uwa-eyepiece-astro.html

They call the eye relief "Exit Pupil length distance" and give 18mm.

[mental4astro]

Fast Newt's, binos and fast refractors are all very different optical beasts. They all present very different focal plane shape and other challenges for an eyepiece to deal with. And for an eyepiece to deal well with each scope design, it is staggering. The price tag is not a surprise, nor is it that this eyepiece comes in just one single focal length - to create a line of focal lengths that perform the same like this piece in so many different scope designs is close to impossible. We see this performance variation in all brands and models. BUT, we do see that there are some single focal length pieces that do perform exceptionally well in different scope designs, like this Docter. None of these eyepieces cost chicken feed either!

If someone does manage to get their hands on one of these Docter pieces, I hope they will be able to give a review using the eyepiece in different scope designs, Newt, SCT, refractor, etc, not just the one. Neat too, not just with a coma corrector or other devise. With so many combinations of scope and eyepiece, it will take some time to complete! Oh what a dreadful, loathsome task... :sadeyes: :lol:

[warpsl]

denkmeier d14 is very close to doctor 12.5,although the view is only 70 degrees,as opposed to nearly 88 through doctor aspectum.

[FlashDrive]

This is an extract from CN ... Credit to Stephan.


I can tell you about my binoviewing experience with two Docter UWA 12.5, but nothing about the Naglers (I don't have any Naglers). I recently purchased a pair Docter UWA 12.5 for my Baader Mark V binoviewer. Some positive remarks of our "Dr. Homma" (Tammy) encouraged me to purchase them.
First and most important, if you are interested in the Docters, a strong and rigid focuser is absolutely mandatory, able to support a 6 lbs. load without stress and able to hold that load in focus even with tube in full vertical position.

First the good things:
The first impression was very positive, these are quite heavy and decent looking eyepieces. And yes, the Docter UWA 12.5 pair work fine in bino action. I don't have any problems with merging both views and found the eye placement to the eyepieces very comfortable and relaxed. Due to the quite compact (55mm) body diameter of the UWA 12.5, there remains enough space for nearly everyones IPD and nose (my personal IPD is 62/63mm, and yes, I have a quite large nose). I fully agree with Tammy, these are outstandingly comfortable UW-eyepieces (84°) for binoviewing.

My first light test scenario for both UWA 12.5 was as following: Takahashi TOA-150B f/7.33 (with reinforced 4" standard focuser) -> Baader 2" ClickLock clamp for Tak -> Baader 2" nosepiece #16 -> Baader Fluorite Flatfield Converter (FFC) set at approx. 4.5x focal extension -> Baader T-2 1 1/4" Maxbright diagonal mirror -> Baader Mark V bino (without any glasspath corrector inserted) -> 2x Docter UWA 12.5. Resulting magnification of this combo is about 396x at f/33.

Test object was the Moon and first light with the UWA's 12.5 was simply breathtaking. They deliver a widefield image sharp over the entire field, with perfect detail definition and brutally hard contrast. Absolutely no false colors visible at moon limb, no matter if looking at the center or the outermost edge of view. The background perfectly deep black like velvet. I felt really impressed (or should I say shocked) by the UWA 12.5. There remains no doubt that the UWA 12.5 is an absolutely outstanding and very comfortable widefield eyepiece, perfectly harmonizing with a binoviewer, even when pushed to high powers. I wouldn't hesitate to recommend them to you, if your focuser supports such a load as previously stated.

I can see by this report that I may be up against a focuser issue ...my TV Genesis Focuser may not be enough to handle the ' weight ' of 2 x Docter and a Bino combination....I will have to see.
When it arrives, I will put my Bino on my Scope and place the Docter eyepiece into it ....make a judgement that way.

See what happens ......Col..

[Kunama]

Don't worry too much Col, all is not lost, my TOA focuser will hold it just fine ;):thumbsup:

[LewisM]

DIBS!!!!;)

I am SURE my FS78 or FC100 will handle it when you sell it Col :)

[Allan]

There's one on Astromart now for $600USD if anyone is interested.;)

I considered one, but the fact there is only one focal length is a deal breaker. Plus I prefer 100 degrees in the mid and long focal lengths to help frame the big targets at lower power.

The Docter is very popular among the glasses wearing crowd who sometimes struggle with the Ethos a bit.

[FlashDrive]

Photos of size comparison with other TV Eyepieces.

I doubt I'll be getting a 2nd Docter Eyepiece, as the Focuser on my TV Genesis is not suitable to hold the ' extra ' weight ....
Will certainly enjoy using just one anyway...

Credit to Tammy on CN for the Photos.

Col....

[Kunama]

see post #26 above ;) Size seems to be similar to the Vixen LVWs so may not suit narrow IPDs

[FlashDrive]

LVW's work OK for me in Bino's ....may consider getting a pair of 13's or 17's soon .... the 24 pan's are a delight to use....very comfortable viewing, looking at Eta, the Nebula just fills the whole view... ( intermediate low power with a 68* degree fov ) ....brilliant match ...

Col.....

[FlashDrive]

:clap: ....it's almost here.......

Your item was processed through a facility in AUSTRALIA on April 26, 2015 at 11:49 am. The item is currently in transit to the destination.

Flash...

[wavelandscott]

I hope it arrives soon and that you get fine weather to enjoy it. By all accounts it is a gem of an eyepiece.

[FlashDrive]

Thanks Scotty ....you bet ...clear weather ....and no mosquitoes ... ;)

Col....

[LewisM]

Must be sower getting to Deception Bay than here - my OLD MEF focuser (different style fine wheel, different reduction)cleared Customs 26th, arrived this morning :)

Now just making a torque plate for it (again different to the current MEF's).

Now, I am quite happy to test your Docter Col... just let me know, I promise I'll return it quickly (considering local time dilation, I estimate that to be 27 years... give or take a few) :)

[Kunama]

I rang them and gave them my address as an amended delivery address!!!
Waiting patiently for the Docter!

Got my Feathertouch MPA from Wayne at Starlight this morning, smooth as silk again, they replaced all the internals and recalibrated the thing. Might put it on the TOA with the new pinion.

[ausastronomer]

Actually Matt I am sure between the two of us we can do an excellent job of conducting a full review on Col's new eyepiece for him. I have used the 12.5mm Docter a few times but have never had one in my mitts long enough to do a full A/B comparison against all the competition. Between us we can provide plenty of eyepieces for comparison, I have a 12mm Nagler T4, a 13mm ETHOS, a 14mm Pentax XW and a 12.5mm UO HD orthoscopic. You have a 13mm Vixen LVW at least, plus others probably.

I have a couple of premium Newtonians and you have a couple of premium APO refractors. Someone would probably be able to turn up with a big SCT; but I think that might only make such a fine eyepiece squeal in pain as it came out of a newt or refractor focuser and fell into a big cat eye. :)

Cheers,
John B

[FlashDrive]

Ooooh .... :poke: ... did you now .....!!

Well I told them where to send the ' Bill ' ......:rofl:

Col......:D

[Kunama]

I like the way you think John ! Yes I can come up with a few options to compare the Doc to. ;)

[FlashDrive]

... arrived this morning at 7.35am by Courier ....

Bring on the Night....

Col.....:D

[Camelopardalis]

I'll volunteer to put that to the test :lol: who wants to give me a big premium newt? ;)

[LewisM]

No doubt about it Col, you are a junkie. Is there an eyepiece obsession help clinic? :)

Very gaudy box for a German product - usually so restrained and "old school", but boy is that leather case typically German (I had similar with my WW2 German optics items). Quality all round.

Now you need a big Tak to put it in. I hear Matt is wanting to sell his TOA for a fictional 140mm fluorite doublet... :)

[Kunama]

It sure ain't a lightweight !!!
Looking forward to your review.
No the TOA is not for sale !!!

[FlashDrive]

Just over 1/2 kilo.....

Col....

[FlashDrive]

So far I have looked at Jupiter and Moon and I have to say, this is the most ' sharpest ' - ' contrasty ' - ' comfortable ' Planet viewing eyepiece I have EVER used .....

The Moon is breathtakingly sharp to the edge....right across the fov.
Craters reveal such ' sharp ' edges and shadows flow into the terminator with distinct clarity.

I was looking at Jupiter even before the Sun set to the west ... again, very sharp , the Bands stood out as clear and distinct as ever and the view was pleasantly bright.

Focusing is very ' spot on ' ....move it a little each way and you have ' missed ' it.

From what little use I have had with it so far ~ about 1 hour .. Saturn is going to be a real treat to see....without a doubt.

I have to get up early .... so jewel box / Omega and Eta will have to wait till tomorrow night ... barring bad weather..... be interesting to see how it performs on DSO etc.

Am I happy .....answer...... is the Pope a Catholic ...!!

Col......

[Kunama]

Sounds very promising Col. I'll bring my gear up there sometime over winter for a comparison.

(You will also have a delivery of 2 parcels tomorrow, keep on tracking' )

[rrussell1962]

Col, just look at what your new eyepiece has done to the weather! Seriously though if you want to do a review in different 'scopes we can drag out the Obsession, the 8se and the TSA120 one evening when the weather clears up. No - not just an excuse for me to get my eye on the end of it!

[N1]

Flash, how are you liking the Docter? Have you had a chance to do some more observing? :jump2:

[FlashDrive]

See here....

http://www.iceinspace.com.au/forum/showthread.php?t=134724

Flash....

[ab1963]

Hi
I have recently purchased the docter eyepiece and don't claim to be a expert in the hobby but last night I had my first opportunity to use it extensively and all I can really say is that its the most fantastic experience in this hobby I have had so far,it is so immersive ,sharp and contrasty and gives you a feeling of being out there litarally,dark background with very natural colouring with a depth of field I have not seen in anything else I have ever viewed through,i feel like I got my moneys worth last night and the price tag is small potatoes for the experience you get,blows my mind thinking what the view would be like through a set of binoviewers

[Don Pensack]

I did a comparison of the Doctor 12.5mm and the TeleVue Nagler Type 6 13mm last night.
A few remarks:
--the Docter is more difficult to use and hold the eye exactly enough in position to avoid blackouts and still see the field of view.
--the Docter is possessed of an unusual amount of angular magnification distortion, such that a globular cluster moving toward the edge as the scope drifted actually compressed in the radial direction and distorted noticeably.
--it could not be used as a 2" eyepiece in the Paracorr because it required more out-movement than the tunable top allowed. It could only be used as a 1.25" eyepiece. That's not unusual--the 6mm and 8mm Ethos are the same way.
--the Docter was not any brighter in terms of the field, or faintest stars seen, than the T6.

Overall, it was not sharper than the Nagler; nor did it produce a brighter image; and it was more noticeably distorted at the edge for astronomical use.

I note, however, that the things I found less favorable for astronomical use might make the daytime use better. If residual AMD is visible, then RD is reduced, and that would make daytime images better. Likewise, any illumination difference between it and the 13 T6 would be unimportant in daytime use.

For this observer, though, many years of 13mm T6 usage came flooding back to me, as that eyepiece is one of the 5 sharpest I have ever owned out of 315 personal eyepieces owned. Had I not replaced it with a 13mm Ethos (I'm one of those for whom the wider undistorted field is a plus), I could have happily lived with the 13mm T6 for the rest of my life.

[N1]

Thanks Don for this write-up. Keeping my 13T6.

[FlashDrive]

Don.....You should have gone to ' Spec Savers ' :P:lol:

I love my Docter... :love2:

Flash :D

[ariefm71]

I'm keeping my 13T6

[ausastronomer]

Hang on I just get a shovel outta my shed. I would bet London to a 2 bob knob of goat shyyt that a couple of you that have expressed an opinion here, have never seen a 12.5mm Docter, let alone used one.

Cheers
John B

[ausastronomer]

Arief, Mirko,

Have either of you ever actually used a 12.5mm Docter in a decent telescope?

Cheers
John B

[Allan]

G'day Don. I don't see this mentioned anywhere, wondering whether you have. But, I see strong rectilinear distortion in my Ethos when I use them in my NP101is. I just put it down to a combination of the ultra wide eyepieces struggling in the wide FOV of the refractor. The Ethos in a typical dob FOV I find essentially perfect. Delos in the NP101is are absolutely perfect.

[N1]

I was genuinely interested in doing so, but after reading this from a seasoned eyepiece expert:



I will most certainly NOT go out of my way for it now. Unless of course, advice from even a "seasoned eyepiece expert" should be taken with a grain (or a mountain) of salt. Probably not a bad idea:



Yeah the mods have been slack, haven't they? Allowing lowly Docter non-users to have an opinion AND post it in this thread. :lol::screwy:

Finally, if you think I shouldn't keep my 13T6, feel free to make me an offer. :D

[ausastronomer]

Hi Mirko,

Sometimes we need to see the forest through the trees.



Well of course Don is an eyepiece vendor and Televue Dealer who sells Televue Eyepieces. (http://www.eyepiecesetc.com/) Don doesn't sell Docter eyepieces. Even prior to starting his own business with eyepiecesetc.com ; Don was an employee of Scope City who also sold Televue eyepieces.



The 13mm Nagler T6 is an excellent eyepiece and anyone who owns one and likes it has no reason to replace it with anything else. If it was the the only eyepiece available at this focal length would I be happy? Very happy, I would have one. Do I think it is the equal of the 12.5mm Docter? Not even. It's also inferior IMO to the 14mm Pentax XW and the 13mm ETHOS (both of which I own) in many respects and I rate both of those behind the Docter.

While I don't own a 13mm Nagler T6 it's an eyepiece I have spend a lot of time with over a lot of years. We have 4 of them in our 3RF eyepiece kits. 2 that go with 2 different 18" Obsession telescopes and a pair of them for the 12" binocular telescope. I also helped Mike Salway do the testing of the 13mm Nagler T6 and all the other eyepices in this review 10 years ago.

http://www.iceinspace.com.au/42-245-0-0-1-0.html

I already own a number of eyepieces at this focal length including a 12mm Nagler T4, a 12.5mm UO HD Orthoscopic, a 13mm ETHOS and a 14mm Pentax XW. I have never wanted to replace any of those with the 13mm Nagler T6. In fact when combined with a paracorr the 14mm Pentax XW gives it a horrible hiding. The Pentax clearly goes deeper with better light transmission and contrast on threshold targets for any given telescope aperture. For instance on 47 Tucanae using a 10" telescope the 14mm Pentax XW shows a lot more stars in the core than the 13mm Nagler T6. On HN40 which is the multiple star at the centre of M20, the 14mm Pentax XW easily shows the "d" star with direct vision in my 14" SDM whereas the 13mm Nagler T6 struggles to show it with averted vision. The 13mm Nagler T6 does have a larger AFOV and is a lot smaller and lighter. The 14mm Pentax XW has much better eye relief and is a lot more comfortable to use IMO. Size, weight and AFOV aren't so important for me. I will add a comment here. The 14mm Pentax XW does exhibit field curvature in many telescopes, including all my Newtonians. However, when combined with a Paracorr the 14mm Pentax XW offers a very sharp flat field view right across the entire FOV and I prefer it to the 13mm ETHOS and the 13mm Nagler T6. Without a Paracorr I would take the 13mm ETHOS every time.

I have also used the 12.5mm Doctor on a couple of occasions. At no time have I ever had any issues with comfort, ergonomics or eye placement with it, nor have I ever read anything to that effect from anyone who has used it, other than Don. In fact I find it be one of the most comfortable easy to use eyepieces I have ever used. In fact, the overall viewing experience with it in terms of comfort, ease of use and optical performance, is about the best I have ever had from any eyepiece I've ever used, and I 've used a lot of them, over a lot of years. I am aware of about a dozen online reviews of this eyepiece and most express a similar opinion to mine. Don is the first person who has not been totally impressed with it and the first person who would not put it clearly ahead of the 13mm Nagler T6 in a direct comparison.



Well they have because on a properly moderated and controlled forum like Cloudy Nights, Don would not have even been allowed to make that post as he is classified as a vendor and precluded from commenting on products that he sells, unless asked a direct question about his products; and he is not allowed to comment on products sold by other vendors. Slight conflict of interest there don't ya think? And I know that because I have been a moderator on the eyepieces forum on Cloudy Nights for over 5 years :)

Cheers,
John B

[simmo]

Why are eyepieces so controversial? Take a chill pill and just enjoy what you got. :)

[Moontanner]

No need for chill pills. It's great to see some varied opinions from people with different types of experience in the matter.

It's only controversial because there is the potential for people to spend
substantial amounts of money on these things in worthwhile volumes. That makes it a hotly contested area for businesses, and one which will always attract plenty of attention. (15 odd years of selling non astronomy services to the upper end market is my experience).

Anyway, thanks to all for the reviews so far. I don't have any experience with this particular eyepiece and that's why I'm here.
Keep the comments coming.:thumbsup:

[Don Pensack]

Well, John is right. I am a TeleVue Vendor and not a Docter vendor.
I had heard so much praise for this eyepiece that I jumped at the chance to use it, and I anticipated I would be impressed.

I suppose I should state that I agree with the contention that angular magnification distortion is a bad thing in astronomical observation, whereas a fairly high degree of rectilinear distortion is easily tolerated. A good example of this is the 24mm Panoptic, which gets a lot of praise, but has a ton of RD. Those who cannot tolerate RD don't like that eyepiece.

And the Docter definitely has AMD at the edge. More than other eyepieces I have used (316 personal eyepieces as of this writing) in a telescope at night. I have, however, seen this in many many binocular eyepieces, and it doesn't surprise me that the Docter is supposed to have binocular use as its heritage.

As a cautionary note, I would also comment that I have only used the Docter for about a half hour on about 4 separate targets. And the comparable eyepieces used as test subjects were the 14mm Vixen SSW and the 13mm TeleVue Nagler T6. My comments were from my notes made during their uses and in the immediate comparison as the eyepieces were switched back and forth.

I also note that I do not like long eye relief eyepieces in short focal lengths, preferring eye reliefs of 10-13mm. I do not view with glasses. If the eyepiece has an adjustable eyecup, though, I can usually dial it in so the long eye relief doesn't become an impediment to viewing. The Docter had a long eye relief compared to the other 2, which, while ideal for a glasses wearer, was, for me, a factor that made the eyepiece harder to use.

Those of you who dive into optics know that it is not possible to simultaneously solve both RD and AMD in widefield eyepieces. They either will have one or the other or a bit of both, depending on the point of view of the designer. Generally, RD is thought to be bad for daytime views because it distorts straight lines near the edge of the field, and AMD is thought to be bad in astronomical use because it distorts shapes and separations as objects near the edge.

If the target is held in the center, either form of distortion will be unnoticeable. If, on the other hand, you let the target drift through the field (common in dobs), then distortion will be noticeable and it is likely AMD will be more objectionable.

TeleVue regards AMD as the form of distortion to be limited (so do other eyepiece makers). And the Ethos eyepieces have less than 1% AMD anywhere in the field. Since they have wide fields (100-110 degrees), that means that, because they cannot void the laws of physics, those eyepieces have a lot of RD, regardless of what scope they are used in.

I did not find the Docter to have notable astigmatism, lateral color, or spherical aberration. It is a sharp eyepiece. One of the targets was a planetary with a magnitude 15.9 central star (fairly hard to hold with direct vision on a reduced transparency night). It was about the same in both the T6 and the Docter. As was the view of the planetary itself.
Resolution on a globular (M15) was about equal, with the core resolving into a mass of tiny little pinpoints in each eyepiece--even the Vixen, which was the 3rd place eyepiece in the test because of lateral astigmatism and a slightly curved focal plane. Plus, the Vixen had eye placement issues due to a distortion of the exit pupil that made the eyepiece very hard to use.
The Docter was only hard for me to use because of its long eye relief and the shape of its eyecup. I noticed no exit pupil issues.

I contend it is primarily in the outer 50% of the field that differences between eyepieces show up. And some issues there can be overcome for a particular observer if other characteristics, such as eye relief, or rendition of colors, or other things are more favorable for that observer.

I am an amateur astronomer first, and like most of us, I have my likes and dislikes. The first thing I do when I put an eyepiece in my scope is to focus, then look at the edge. It is where the differences lie. Sure, other things are important, too, but for me, edge astigmatism or EOFB automatically disqualifies an eyepiece for me as a possible purchase. Strong field curvature I cannot accommodate also removes an eyepiece from consideration. The Docter has none of those.

Other observers might first look at eye relief, or contrast in the image, or apparent field, or overall sharpness of the star images (if you are blessed with good seeing), and I look at those things too. The Docter, to my eye, is an excellent eyepiece in many regards, but I still feel it is not superior to the T6 Nagler. And definitely not to the Ethos. That some people think so may be a reaction against the larger FOV of the Ethos, or its reduced eye relief, or its size and weight, IMO, and not likely due to its optical image quality.

I will view with my friend again in the future, and I will take another look at the Docter in my scope. I don't like the AMD, but like I said, people who primarily view at the center won't notice it.

I want to state, however, that my inventory does not influence my opinions. There are many fine eyepieces I don't sell, but think quite highly of (Pentax XW, Nikon NAV-HW, etc.). When i post, I post as an amateur astronomer, not as a dealer. You will never see me "pimp" a particular product.

[ausastronomer]

Hi Don,

Excellent post.

That now puts things into better perspective and most importantly highlights the subjective areas which are most important to you and in many cases are less important to other observers.



The above is a classic case of this. Whilst I don't like eyepieces which are not sharp right across the field, AMD is obviously less important to me. I always try to observe with the target properly centred in the FOV as there hasn't been a telescope invented yet that will give identical image quality at and near the EOF, as it gives on axis. My 3 main dobs all have tracking and I continually keep the target centred in the FOV. I also use a paracorr. I have another 10" dob which does not have tracking, but I always hand track with it to keep the target centred in the FOV. I laugh when I see people recommending to others to observe in sub F6 dobs, without a paracorr, using the drift method. In this scenario irrespective of how good the optics in the telescope are, image quality towards the EOF will be less than 1/2 wave due to comatic blur and it gets a whole lot worse as the eyepiece focal length increases.

I knew you were calling this as you saw it and not letting your business interests cloud your judgement, but you just see it differently to me and many others, as you place a lower emphasis on points which are more important to others and vice versa.

BTW You and Pam need to get back down here again for another Ozsky. 2016 was fully booked a month after April 2015 finished, but you should book in for 2017; or do you need to sell more Naglers first :)

Cheers,
John B

[simmo]

:) :thumbsup:

[wavelandscott]

One of the interesting (to me) things about this thread is that in the end it reinforces that there really is no single "best of" eyepiece that is perfect.

Like many things, the answer to what might be "best" is dependent upon many factors and in this case differing preferences. For those looking for their own "best" piece of eyepiece gear, there is no substitute for experience with a variety brands and designs. Get out under the stars, use what you have and learn what you like and then choose appropriately.

Clear Dark Skies to all!

[FlashDrive]

Spot On :thumbsup:

Col.

[N1]

Someone has done a quick comparison between a Baader Morpheus and a Docter UWA (among others) in the field, post #1174939:

http://forum.astronomie.de/phpapps/ubbthreads/ubbthreads.php/topics/1171737/Baader_Okulare_morpheus_76#Post1171 737

Use Google Translate.

[ab1963]

I think that it is important to mention that the man Alex who did the review on some level works for Baader I believe as one of the posts that comes up in response states,i think that is something to take into consideration

[N1]

Yes, someone did point that out further down in the same thread, and Alex replies that he is some sort of freelance reviewer whose customers include, but are not limited, to Baader Planetarium.

[ab1963]

but has no affiliation with televue or docter so makes the point important

[clive milne]

I agree.

I find it interesting that the Nagler T6 should be offered up as a benchmark.

I have found it to be a singularly unimpressive design to the extent that I wouldn't consider purchasing one at any price that would be conceivably profitable for the manufacturer.

The T4 on the other hand ticks a lot of boxes for me.

Is the T4 eminently superior to the T6? Not at all.
Clearly, there is a physiological component to the merit function of eyepiece design which is difficult to quantify.

And let's be frank... on any given night, there is an order of magnitude less variation in the qualitative visual experience across the gamut of potentially competitive eyepiece choices than you will find as a result of other factors too numerous to list.... (which I wont, given my current level of dgaf)