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Dream Eyepiece Collection - At Last !

johninderby

By johninderby
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johninderby

johninderby

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Dream Eyepiece Collection - At Last !

It's taken awhile but I've finally managed to put together my dream eyepiece collection.

  • Televue 3-6 Nagler Zoom
  • Televue 6mm Ethos
  • Televue 10mm Ethos
  • Televue 17mm Ethos
  • Televue 26mm T5 Nagler
  • Baader MPCC
  • 1.25" Supreme APO barlow element
  • B&W Outdoor Case - Type 30

I've gone through quite a few eyepieces over the last few years, but after finding out just what focal lengths I used most often I distilled it down to something that could be achieved with just 5 eyepieces and suits everything from my 4" APO refractor to my 14" dob. Thanks to a sizeable contribution from the family (birthday present) towards the 26mm Nagler and the proceeds of selling some astro gear I was able to finish off the collection sooner than expected.

The Nagler 3-6 zoom is a great high power lunar/planetary eyepiece with the flexibility of a zoom, but still as good as any other Nagler. The APO barlow element can be added to make it into a 2-4 zoom without any degradation in performance at all.

The 6mm Ethos is also used for lunar/planetary in the 4" APO and the dob, and is one of the sharpest eyepieces with the best contrast I've ever used for planetary observing. The only other eyepiece that I've used that compares to it in performance is a TMB 5mm Supermono that I used to have. Yes it's got that 100 degree FOV but it's the optical performance that stands out the most to me. The APO barlow element also works well with this eyepiece as well.

The 10mm Ethos performs just as well as the 6mm when used as a high power eyepiece in my Mak or as a medium to higher power eyepiece in my APO or dob.

The 17mm Ethos is my medium power eyepiece and there's nothing more that I can add that hasn't already been said in various reviews, fantastic eyepiece.

The 26mm Nagler T5 is a great low power eyepiece. I chose it over the 31mm Nagler (they were about the same price) as it will be mainly be used in a fairly light polluted urban environment. The 31mm would have some advantages under really dark skies but that's not where it would be used very often. Also the 26mm is smaller and lighter than the 31mm and as it's about the same weight as the 17mm Ethos the two can be swapped around without rebalancing the scope.

B&W Outdoor Case - Type 30. Not cheap, but worth every penny when you consider the value of the eyepieces inside. "B&W protective cases that offer total protection for your equipment. Unbreakable (withstands a 3m fall onto concrete), watertight down to 5m, airtight, dustproof, chemical resistant and corrosion proof".

John

PS

Yes I'm the one responsible for the cloudy and rainy weather forecast for the month of August.

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johninderby

johninderby

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Hi Steve

It depends on what the seeing is like. On a good night I start with the 17mm Ethos, but if seeing isn't that good I prefer the 26mm Nagler. It copes better with poorer seeing conditions. If it's going to be lunar/planetary I start with the 6mm Ethos.

Actually I haven't really had that much observing time with all the eyepieces :):) as I've only just completed the collection, but I can't wait for the darker nights to really put them to good use!

John

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johninderby

johninderby

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Here's a couple of photos showing the Baader Multi Purpose Coma Corrector (MPCC) fitted to the 17mm Ethos and the 26mm Nagler.

  1. To get the correct distance for the 17mm Ethos you need the Baader T2-25C T2 Extension Tube (7.5mm) and the Baader T2-29 Expanding ring M48/T2.
  2. For the 26mm Nagler you need the Baader T2-29 Expanding ring M48/T2 and the Baader HDFT-14 Fine Tuning Ring.

John

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Ben Ritchie

Ben Ritchie

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For the 26mm Nagler you need the Baader T2-29 Expanding ring M48/T2 and the Baader HDFT-14 Fine Tuning Ring.

That's interesting, for the 31mm Nagler I just use the Baader HDFT-28 Fine Tuning Ring - wonder if i've got the spacing wrong? What does the T2-29 expanding ring do, as I don't appear to be using one...!

With the MPCC + spacers the 31mm looks a bit like one of those German hand-grenades from war films :)

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Ben Ritchie

Ben Ritchie

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By the way, how do you find the MPCC + 17E? From what i've read the MPCC design introduces spherical aberration but at low powers (e.g. your 26T5 or my 31T5) you can't see it. However, it apparently becomes an issue with ultrawides at higher powers, where you have TFOVs wide enough to need coma correction but powers high enough to see the SA.

I've yet to try my 13E + MPCC (fiddly to swap it over from the 31T5 in the dark) but probably should get some sort of coma corrector for it

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John

John

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Fantastic set John - crongratulations !.

I'm very interested in your selections as the owner of a 4" ED refractor and a 12" dobsonian.

The Baader MPCC is something I've had my eye on for a while for use with my dob.

It's interesting that you've ended up with a Tele Vue dominated range (as have I) - did you try other premium brands (eg: Pentax) on your "journey" or have you always leaned towards the "black and green" ?.

Do you find the Nagler zoom a bit "claustrophobic" after the Ethi ? - I had one for a while but found I (marginally) preferred a range of T6 Naglers - mainly because of the wider FoV.

Thanks for posting the details - always good to read about other peoples thought processes.

John

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johninderby

johninderby

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I got the info on which spacers or rings to use with the MPCC from Alpine Astro where they've done all the testing to work out the exact ones needed for most popular eyepieces. The T2-29 is just used as a very small spacer ring. They recommend the same spacers for the N31 as for the 17E.

http://www.alpineastro.com/optical_accessories/MPCC/mpcc_visual.htm

Here's anothor photo showing the spacers/rings spread out with the eyepieces.

I haven't used the 17E with the MPCC yet. I replaced a Paracorr with the MPCC as it just so lightweight in comparison and fits inside the focuser right out of the way. Actually I haven't been tell any difference in performance between the two.

I suppose with having the three Ethoi (ethoses?) and the zoom I thought I might as well finish off the collection with the N26, although I did consider the Pentax XW30 which is a great eyepiece in it's own right. The zoom is used mainly in the 4" on an Alt-Az mount which is my grab'n'go scope and is ideal for lunar/planetary quick looks (nothing extra to carry). Particularily usefull at this time of the year! As it's only for high power the zoom's small FOV isn't a problem.

I'm going to be using the set with my 4" ED APO, OMC140, 10" dob and a 14" dob. Can't wait for the real dark nights when the collection will get a proper workout.

John

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Ben Ritchie

Ben Ritchie

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Actually it's 21mm John - and it's due soon :)

Tele Vue Optics Article Page

I'd get that 26mm Nagler on the market soonish if I were you :)

John

Aw, nuts. That's the one i've been waiting for ... not quite the same TFOV as the 31mm Nagler, but larger TFOV than the 26T5, better exit pupil for my environment and the logical jump from the 13E without reshuffling the rest of my collection. Looks slightly heavier than my 31T5, so a big bit of kit.

OPT's got mail. Anybody want a 31T5 in due course :p

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johninderby

johninderby

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Pity the new Ethos isn't a 24mm, that I would definately have gone for. When it comes out at Christmas time wonder what the pricing will be? I'm guessing about £629.00 or so. If it does end up in that price range or even higher, the 26mm Nagler may be hanging around for a while.

Given that for technical reasons 21mm now seems to be as big as the Ethos line can go, the only other possibilty is something smaller than the 6mm. Now if they came out with a 3.5mm Ethos, that I would grab right away.

I wonder if an Ethos zoom is possible? :)

John

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Ben Ritchie

Ben Ritchie

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Given that for technical reasons 21mm now seems to be as big as the Ethos line can go, the only other possibilty is something smaller than the 6mm.

Reasonable speculation is that you could go bigger than the 21mm Ethos (the 2" format allows it) but the size/weight would increase substantially - similar to the Nagler T5 series which gets much bigger as you go 20mm -> 26mm -> 31mm and also never hits the maximum field-stop allowed by the 2" format. So the 21mm is a sensible balance between size/weight/cost on one hand and a reasonable increase in TFOV over the 17mm on the other. It's also a great pair for those of us with the 13mm.

As for the Ethos zoom... :) :)

Next up, 2.7" eyepieces? :p

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calibos

calibos

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John, can you tell us more about the Supreme apo barlow element?

I did a google and had a look at it but I can't see it in your image in your OP. Is that actually it front row on the right. ie. You've removed the lens element from the barrel? Can I assume it screws into the 1.25" filter threads in the 1.25" barrel of the Ethos 6. If this is so have you tried it on your 8E and 10E. What magnification factor is it giving.

The reason I ask is that although I am not in the market to start trading in my Hyperions till Spring '10, I am making a heated scope mounted EP box now and wanted to drill the rack with the hole spacings to suit a collection of Ethos Ep's instead of my Hyperions. This then led to me doing much more thorough research on the Ethos range than before. ie. I started calculating mags with my Paracorr in place. I found some planetary and lunar mag gaps I wanted to fill which of course led me to reading up on the Big Barlows and Powermates. The prospect of a Powermate -> paracorr -> Ethos stack protruding out so far from the focuser scared me however. I know the paracorr wouldn't be needed at high mags anyway, but it still seemed like a big old optical stack sitting out.

Then I remembered this thread.

So can you tell us what the mag factor of the barlow apo element is. How it works, effect on eye relief etc. How it works on the 8 and 10 as well as the 6 etc

Thanks in advance

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johninderby

johninderby

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Hi

I just use the Supreme barlow element on it's own and it does just screw into the eyepiece's 1.25" barrel. It gives a 1.5x magnification. I only use it on the 6mm as with the 10mm it would give a 6.6. I sold the 8E and replaced it with the 6E. One thing I really like about the 6E is that it's not that big or heavy an eyepiece, more of a "normal" size which makes it very convenient to use.

The APO lens element is made in Japan and is as good as any 1.25" Televue barlow, costs a little more actually. In use it just "disappears" in that you can't tell you're using a barlow, except for the increased mag of course. I also use it with my 3-6 Nagler zoom as it makes it into a 2-4 zoom with no loss in performance.

I sold my Paracorr and replaced it with a Baader MPCC as it works just as well and fits completely inside the focuser and is only a fraction of the weight. Yes you do need to use different spacer rings for most eyepieces, but as it's only used with the 17E and 26mm Nagler it's no problem. The 17E and 31mm Nagler would use the same spacers by the way. I find it's just not needed with a 10mm or less eyepiece, and even with a 13mm it's not really needed either.

When I chose the eyepieces in my collection I based it on what eyepieces I actually used the most, which were something in the 3 or 4mm range and a 5mm, 9mm,16mm and 25mm.

John

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calibos

calibos

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Can I run this by you John. The scope they will be used in will be a 16" FL1828mm servocat equipped Lightbridge with a Paracorr for the long FL Ep's

With Paracorr (Effective FL of 2102mm)

  • 31mm Nagler - 68x
  • 21mm Ethos - 100x
  • 13mm Ethos - 161x
  • 8mm Ethos - 262x
  • 6mm Ethos - 350x

Without Paracorr but with Supreme Barlow Element (Effective FL of 2742mm) for nights of great seeing of which i seem to get about 5 or 6 a year.

  • 6mm Ethos - 457x

The way I look at it is I can leave out the 17mm Ethos because it would give me 123x which is too close to both the 21mm and the 13mm Ethos in magnification. I think I can also leave out the 10mm because it would give me 182x which is too close to the 13mm and 8mm Ethos in magnification. With the Supreme element it would give 274x which is too close to the 6mm Ethos.

This way I can leave the Paracorr in the focuser 99% of the time for convenience and only have to remove it and attach the Supreme Barlow element to the 6mm when Lunar or Planetary observing during periods of exceptional seeing. Otherwise the 8mm and 6mm in combo with the paracorr give me some nice Planetary and Lunar mags for times of average seeing.

Can you give me your expert opinion on that spread of mags? Do you see any gaps that need filling for instance.

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