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Go Back   IceInSpace > Equipment > Eyepieces, Barlows and Filters

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  #21  
Old 22-01-2019, 08:31 AM
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LewisM
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Quote:
Originally Posted by bratislav View Post
I've sold my Masuyama set (5, 7.5, 10 and 15) to an eyepiece collector in US and never really looked back. Yes, they are decent, but not really magic (contrary to what many people try to make them into).

The only regret I have is not keeping them a bit longer, I could have made even more money
I disagree to a point - I founf the Masuyamas wanting in reflectors, but fantastic in refractors.

I have the same opinion as yours though about Televue. Never used a single TV EP I found to be excellent - all were good, and merely that. None were exceptionally sharp - I found Vixen LV EP's better in terms of sharpness and disc size. As such, there is not a single TV EP in my tiny collection (Parks only now)
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  #22  
Old 22-01-2019, 06:14 PM
bratislav (Bratislav)
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Originally Posted by LewisM View Post
I disagree to a point - I founf the Masuyamas wanting in reflectors, but fantastic in refractors.
Eyepieces don't really care if you use them in refractor, reflector or catadioptric. All they care about is how fast is the incoming beam (f-ratio), how curved is the field and what off axis aberrations they are presented with. In some cases for example eyepiece's astigmatism can add to telescope's astigmatism (and off axis correction becomes really bad), in some rather special cases (like Jones-Bird and a Plossl) they will cancel and you can enjoy nearly perfect view, despite both scope and the eyepiece being decidedly non perfect. But this is a rather unique scenario (as is now long gone Pretoria with its negative coma, targeting Newtonians). These days eyepiece designers try to make them as aberration free and as flat as possible (so their creations can be used equally in all different telescopes).

Quote:
I have the same opinion as yours though about Televue. Never used a single TV EP I found to be excellent - all were good, and merely that. None were exceptionally sharp - I found Vixen LV EP's better in terms of sharpness and disc size. As such, there is not a single TV EP in my tiny collection (Parks only now)
You must be either much more critical observer than me or have access to some incredible optics. None of my telescopes measures significantly better than 1/35 wave RMS on the front (although my 12" gets close).
Both Type 5 and Type 6 Naglers as well as Ethos' add approx 1/35 wave to the telescope's wavefront (measured by French AiryLab), so telescope would have to be much better than that before we start to blame the eyepieces for any loss of sharpness. Not to mention that your eye too has to be capable of detecting wavefront residuals well into 1/50, or better yet, 1/100 wave.
If you really could see that much degradation to "disc size", my hat is off to you.

I just don't get obsessed with eyepieces. Larger scope or better mirror (or both) will always show more to any object even if used with vastly inferior eyepieces.

But I do understand very well that arguing eyepieces is much more emotional than analytical (it is hard to do objective assessment to something that you either like or not like). It is little bit like arguing audio cables - I keep saying to some of my mates that it will be much more of an improvement if they invested $$$ into better speakers rather than a piece of wire, but that advice invariably always falls to deaf ears. Even if I'm usually the one blamed as being deaf.
Or blind in this case
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  #23  
Old 22-01-2019, 07:12 PM
Wilso (Darren)
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Hi Ang026,

Both the Masu 16 & 10mm are easy to use, I've only had the chance to use the 10mm once for terrestrial but seems to be the better corrected eyepiece of the two. (at f4.5) No blackouts or kidney bean effect to be seen. Eye relief is only 6.5mm in the 10mm eyepiece but that didn't bother me either.
Give me a couple of weeks to try it out and I'll post it if I find anything else.

Cheers
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  #24  
Old 05-02-2019, 06:59 PM
Wilso (Darren)
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Managed to compare my Masuyama and Tak Le eyepieces on Saturday night, both 5 element 3 group eyepieces. Used my Fsq 85ed with the 1.5x extender, no eyepiece had the same fl. Edge performance of the new Masu 10 and 16mm improved greatly off axis at f8 compared to the native f5.4 of the scope. Very happy there, but out of the two I think the extra eye relief, sharpness and large eye lens of the 16mm proved the more immersive eyepiece and easier to use.
Also I was surprised how comfortable the older 20mm Masu is to use without the rubber eye cup, they probably should have continued with the same design with the newer models.

Last edited by Wilso; 05-02-2019 at 07:42 PM.
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  #25  
Old 05-02-2019, 07:21 PM
Ukastronomer (Jeremy)
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never heard of them ?
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  #26  
Old 06-02-2019, 05:40 AM
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Masuyama have been around for decades though they have not always been available outside of Japan.

In the UK they are available from FLO.

https://www.firstlightoptics.com/mas...eyepieces.html
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  #27  
Old 06-02-2019, 03:43 PM
Wavytone (Nick)
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Had one ages ago - 35mm I think, and sold it. It was a nice eyepiece in maks and refractors but to be honest nothing magical, and definitely not an eyepiece for newtonians.

The original Masayumas were very good in the era when they were made however some modern eyepieces are just as good and in some respects surpass them.
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  #28  
Old 06-02-2019, 07:27 PM
Ukastronomer (Jeremy)
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Quote:
Originally Posted by anj026 View Post
Masuyama have been around for decades though they have not always been available outside of Japan.

In the UK they are available from FLO.

https://www.firstlightoptics.com/mas...eyepieces.html

How do they compare with the likes of Vixen and Celestrons better eyepieces though
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  #29  
Old 06-02-2019, 08:04 PM
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I have no experience with Vixen or Celestron eyepieces but have several TeleVue and some Takahashi eyepieces as well as the Masuyama 32mm.

What I like most about the Masuyama 32mm is the outstanding contrast and sharpness in f15 refractors. The optical design is dated but the quality of manufacture is up with the best. The 32mm has good eye relief and I find it very comfortable and relaxed to use. It would not be my first choice for telescopes with focal ratios faster than f10. The off axis aberrations would be more and more disappointing as the focal ratio decreases.

The 16mm and 10mm are tempting but I really think I would not like the short eye relief for more than quick looks. I tried hard to like a 16mm Nagler type 5 but in the end the short eye relief was taking all the fun out of it.
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  #30  
Old 06-02-2019, 09:51 PM
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Quote:
Originally Posted by anj026 View Post
I have no experience with Vixen or Celestron eyepieces but have several TeleVue and some Takahashi eyepieces as well as the Masuyama 32mm.

What I like most about the Masuyama 32mm is the outstanding contrast and sharpness in f15 refractors. The optical design is dated but the quality of manufacture is up with the best. The 32mm has good eye relief and I find it very comfortable and relaxed to use. It would not be my first choice for telescopes with focal ratios faster than f10. The off axis aberrations would be more and more disappointing as the focal ratio decreases.

The 16mm and 10mm are tempting but I really think I would not like the short eye relief for more than quick looks. I tried hard to like a 16mm Nagler type 5 but in the end the short eye relief was taking all the fun out of it.

Thanks
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  #31  
Old 07-02-2019, 08:25 AM
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mental4astro (Alexander)
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The key thing about this whole discussion is optical matching - matching the EP to the scope design.

Masuyama eyepieces are designed for refractors. Look at what the Japanese market was using when Masuyama was at its most popular, slow refractors. Wavy mentioned this too. The new Masuyama designs are also totally different beasts from those of 30 years ago.

With EP design being what it is with multi-elements, you will get variations in performance within individual EP focal lengths, not just in focal ratios but also scope types. This goes not just for Masuyama but for EVERY make and design. This is why some Masuyama pieces do better in faster fracs than others, and why some perform better/worse in Newts. You will not find a single eyepiece that will perform EXACTLY the same across all scope types and all focal ratios within each scope type. There will be some variation somewhere even if it all seems bonza... there will be a difference somewhere including ease of use/eye strain, eye placement. AND it will differ with different people (that's why TV offers theiir Dioptrix lenses). EP choice is also a personal choice for what works best for your eyes.

The worst mistake WE can make is pass judgement on an entire line or entire Brand based solely on using one single eyepiece in just one single scope type and focal ratio. Especially when that particular eyepiece is not designed for that scope... It just shows we have no idea what we are talking about. Add blind Brand loyalty/prejudice and the situation gets worse.

I have a 35mm Masuyama. Lovely eyepiece in a Mak and SCT. Haven't tried it in a refractor. In a Newt it is not an optical match and a 32mm plossl does better in a Newt, but the Masuyama craps all over it for transmission. Compared to a Vixen or Celestron (who don't make or design their own eyepieces), in what way? AFOV? Across the entire range? Different aberrations in all scope types? Age of design, older vs current? Brand??? Why not with TV or Pentax? And then too in regards to what parameters?

Last edited by mental4astro; 07-02-2019 at 09:33 AM.
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  #32  
Old 12-02-2019, 06:57 AM
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To each his own.
I have a 4" f/7 apo, and found the new 85 Masuyamas to have way too much uncorrected astigmatism in the outer field. Contrast is good.
Perhaps at f/15 (I used to own an f/15 refractor), they'd be better-corrected.
Modern scopes are typically shorter than f/8, though, so I'm not sure who these eyepieces were intended for.
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  #33  
Old 12-02-2019, 10:47 AM
Wavytone (Nick)
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Quote:
Originally Posted by Don Pensack View Post
I'm not sure who these eyepieces were intended for.
Small refractors, Don... they dominate the japanese market. Hence why they were never heavily marketed outside Japan. Of course you'd see off-axis images as blurry defocussed winged seagulls in a big dob, because the field is curved in the opposite direction to that of a small refractor.

Refractor: Petzval curvature = F/3 (approx) - which is strongly convex towards the eyepiece
Newtonian: Petzval curvature = -F - ie concave towards the eyepiece

PS I very much doubt it's astigmatism because if that were the case the primary mirror would have to be warped and this would be painfully evident in EVERY eyepiece you have.

Last edited by Wavytone; 12-02-2019 at 02:23 PM.
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