44 replies to this topic

[Loren Toole]

Last year, there was a long discussion about Mr Yoshida's ratings,
the list has been updated recently. Ratings for scopes less than
110 mm are listed below (I've extracted this from his larger
list):

(70)Takahashi FS-102 TWIN+EMS
(69)Zeiss APQ100/1000
(68)William Optics10cmF8
(67)TeleVue NP101
(67)Takahashi TSA-102
(66)Zeiss APQ100/640
(66)TAKAHASH FSQ-106ED
(66)NIKON 10cmED
(66)William Optics FLT110
(65)Vixen FL102
(65)Takahashi FSQ-106
(64)TeleVue TV101
(63)TeleVue TV102
(63)Takahashi FS-102
(63)PENTAX 105SD
(61)PENTAX 105SDP
(58)Takahashi FSQ-85ED
(57)TeleVue-85
(56)Takahashi Sky90

While I don't want to debate absolute rankings (+/- a few rating
points, Yoshida doesn't think 3 points difference is significant
based on his method), there are some interesting placements in
his list. First the Televue NP101 is ranked nearly equally with
a Zeiss APQ100. I've used neither scope, but this is a surprise
to me based on discussions related to the lengendary Zeiss. The
other surprise is the nearly equal rankings of TV101,TV102,FS102
and Pentax 105s.

Any thoughts on any of these comparisons? These examples suggest
either his test method can't discriminate closely or differences
are really very small under his viewing conditions (which I've
read are somewhat poor given the urban effects).

[jrbarnett]

So is a lower ranking number better or worse?

Is the Takahashi Sky 90 is the highest or lowest ranked scope on this list?

Thanks,

Jim

[noah way]

Here is the list.

[JayKSC]

The
other surprise is the nearly equal rankings of TV101,TV102,FS102
and Pentax 105s.

Any thoughts on any of these comparisons? These examples suggest
either his test method can't discriminate closely or differences
are really very small under his viewing conditions (which I've
read are somewhat poor given the urban effects).

All of those telescopes are premium class instruments. When you get down to the nitty-gritty details and actual field use, a Tele Vue 102, Tak 102, Zeiss 100-ish, and AP 105 will all perform more alike than different. Subtle differences in sharpness, contrast, and color correction are to be expected, but if I were assigning a percentile performance difference, I'd say all such scopes perform within about 5% of one another on all areas.

- Jay
South Florida

[jrbarnett]

Thanks Noah.

The numbers are actually points. More is better.

I'd be lying if I didn't say some of the placements surprise me a bit. For example a 31% CO Mewlon 210 rated better than any of the refractors on the excerpted list. I have a Mewlon 210 and several of the refractors on the list, and, well, *my* Mewlon 210 wouldn't rate quite as high as the one listed. Better than any commercial SCT I've owned, but not as good any NP-127, NP-101, TV-102, FS-102, etc., I've owned or used.

Regards,

Jim

[roadi]

A litle surprise to me is the placement of the TSA 102 wich is 98% perfect acording to tests I've read (though havn't looked through one) and the relative low raking of the TAK FS102 and last the colorfull Sky90 beeing almost egual to the Televue 85 wich is highly praised by people who used them!

Based one wich criterion are the scopes ranked, pure color corection? contrast and sharpnes? else?

With all respect to mr. Yoshida's ranking list as I believe he is a very experienced person, but based on my visual experience with the SKY90 and an FS102 related to the (3 point difrence hardly detectable) there should be quite more of a gab between these two

By the way, thanks for the interesting new list

[roadi]

Thanks Noah.

The numbers are actually points. More is better.

I'd be lying if I didn't say some of the placements surprise me a bit. For example a 31% CO Mewlon 210 rated better than any of the refractors on the excerpted list. I have a Mewlon 210 and several of the refractors on the list, and, well, *my* Mewlon 210 wouldn't rate quite as high as the one listed. Better than any commercial SCT I've owned, but not as good any NP-127, NP-101, TV-102, FS-102, etc., I've owned or used.

Regards,

Jim

Jim,
did you get your mewlon optics properply aligned? mine did outperform my FS102 quite easily on Jupiter and Mars when seeing permitted wich leaved my FS102 indoor mostly and later sold it wich I do regret a litle!

[BrianFitz]

I have to wonder how a person can rate the best telescopes in the universe aginst each other --- at that level can you imagine how great most of the scopes perform?

Many of these telescopes are chosen for personal choice, brand confidence, personal subjecive reasoning -- Question: is it possible to quantify and come up with this point system or is there some personal influences in his chart? Clearly, from a qualitative stand-point they are all top-notch..

[johnnyha]

What is an "FS-102 TWIN+EMS" and where can I get one?

[roadi]

What is an "FS-102 TWIN+EMS" and where can I get one?

Two FS102 coupled together with pair of these to reach interpupilar distance

http://www.cloudynig...php?item_id=186

[roadi]

I have to wonder how a person can rate the best telescopes in the universe aginst each other --- at that level can you imagine how great most of the scopes perform?

Many of these telescopes are chosen for personal choice, brand confidence, personal subjecive reasoning -- Question: is it possible to quantify and come up with this point system or is there some personal influences in his chart? Clearly, from a qualitative stand-point they are all top-notch..

Fitz,
I agree with all of these scopes to be top of the line! maybe some variance between samples could have a litle influence?

[t.r.]

I recall Mr. Yoshida compares these scopes for ultimate planetary performance. On a scale of 1-100%, the best planetary scope Has been an AP160 and Tak 300 Mewlon. If you think of it that way, there can only be 100, so the rest get compressed into a ranking on how they performed showing planetary detail. So a Tak Sky90 is working at 56% of what you could get with an M300 giving 101% and I'd say it could be desribed as "double" the performance. I was suprised by a short few, but it looks sound to me...really a scaling of aperture and quality...no big suprises. He takes into account absolute detail resolved, color error and ability to take magnification. I wish I had access to the number of scopes he has!

[ken svp120]

In looking over this list I was searching for our mid-range scopes such as Orion, Celestron, Meade, AstroTech, Sky Watcher, etc... I noticed two Orions and one celestron but none of the others. Were these not selected for the testing? Were they not available for testing? Or were they tested but did not make the list? Just curious...does anyone know?

[Eddgie]

While we can question his methods endlessly, I have to say that my own experience using the telescopes I have owned (which is a far more limited sample) seem to correspond to his quite well.

Of the scopes in his list that I have owned, here is the way I would rank them. All of the telescope he and I have both owned or tested have fallen in the exact same placement as his.
C14
6" f/8 Astro-Physics refractor
C11 (note that Mr. Yoshida had the same result.. The C11 did better than some 6" refractors and not as well as others. My experice was the same.. One of my 6" scopes was better than the C11, the other was not).
Meade 152ED - EdgeHD 8" (Tie.. Optics are perfect in the EdgeHD sample I own. Until one has seen an 8" SCT with perfect optics, it is hard to appreciate how good they CAN be)
MN61 - C8 (Tie)
MN56
C9.25 (quite a bit of undercorrection.. A lemon if there ever was one)
Televue 101
Vixen ED100SF
C5 - Televue Genesis (tie, again, this C5 sample has excellent optics)
Celestron 80ED - Vixen 102 achromat

There were plenty more, but I have to go to work now... Anyway, my own rankings match his for the telescopes we have both owned/tested.

[Bob Abraham]

Hi Jim,

My Mewlon 180 very soundly and very consistently beat my old FC-100 and TV-101 on planets (in side-to-side tests). To be honest I didn't find it all that close a call. On Jupiter and Saturn the Mewlon is just a hair behind my TEC-140 (I had the two scopes on the same mount at the same time for a while). On balance I think a Mewlon 180 would run and neck with an FS-128.

These things are all subjective of course! So I'm curious, are the diffraction spikes what put you off when comparing to the refractors? I can easily see how if somebody found them distracting they might rank the Mewlon lower than I would.

Bob

[mclewis1]

YAYLD ... yet another Yoshida list discussion

For those who haven't been on the earlier discussions some common questions are ...
1) why isn't brand X scope on the list?
2) what does he mean that scope X is better than Y? Thats not what I've seen
3) does he really own all those scopes?
4) how come the C11 ranks so high?
5) who is this guy anyway? ... and will he consider adopting me?

[jrbarnett]

Brian:

What you say is true - most of the scopes on the list represent long hours of production effort and a hefty price tag to pay for it. Expectations should be high for each and every such scope.

That said, my issue has to do with the fact that a scope with a large obstruction and very fat spider arms, which undeniably MUST scatter light and displace energy from the airy disc to elsewhere where such energy does NOT belong, scored so well compared to fairly large unobstructed scopes.

Putting that quibble aside, I think the biggest strength of Yoshida's tests is the fact that he is a seasoned observer and likely knows what to look for in rating optics. The biggest weakness, however, is that these ratings are NOT based on same night, same target, matched magnification observations. No matter how experienced the tester, testing optics on different nights (even when using a uniform rating system) is hard to manage consistently.

Very interesting list.

- Jim

[Fomalhaut]

Hi Jim,

My Mewlon 180 very soundly and very consistently beat my old FC-100 and TV-101 on planets (in side-to-side tests). To be honest I didn't find it all that close a call. On Jupiter and Saturn the Mewlon is just a hair behind my TEC-140 (I had the two scopes on the same mount at the same time for a while). On balance I think a Mewlon 180 would run and neck with an FS-128.

These things are all subjective of course! So I'm curious, are the diffraction spikes what put you off when comparing to the refractors? I can easily see how if somebody found them distracting they might rank the Mewlon lower than I would.

Bob

I agree in all of your above statements. Also my Mewlon-180 betters my FCT-100 (and all other 4-inchers that I've looked through) on planets, but it does only so in fairly good to excellent seeing.

During the decades of my indulging in this hobby I have personally looked through 23 different telescopes of all sizes (from the Sky-90 to the Mewlon-250) out of Mr. Yoshida's complete 2010 list so far and do not find any contradictions between my modest personal assessment and his far more comprehensive one.

By the way: Mr. Yoshida seems more or less to concentrate on the high-end range of telescopes. According to what I had read one year ago, he does not own all of these scopes himself, however quite many of them, while the rest are contributed by pals of his. They also seem to perform the yearly updating of Mr. Yoshida's assessment in groups.

Chris

[SteveC]

Thanks Noah.

The numbers are actually points. More is better.

I'd be lying if I didn't say some of the placements surprise me a bit. For example a 31% CO Mewlon 210 rated better than any of the refractors on the excerpted list. I have a Mewlon 210 and several of the refractors on the list, and, well, *my* Mewlon 210 wouldn't rate quite as high as the one listed. Better than any commercial SCT I've owned, but not as good any NP-127, NP-101, TV-102, FS-102, etc., I've owned or used.

Regards,

Jim

I'd question the Intes Micro A-608 besting a TEC140, when my Intes Micro 715 can't beat the TEC140. The IM 715 is a dedicated planetary scope and it isn't even rated(it could be under another Mod #- see #73).

I'd like to view through a 6" ubstructed scope that can beat my TEC140 by such a margin. The IM 607 is rated below the TEC140 and much lower tham the IM 608 at the top.

(90) INTES-MICRO ALTER A-608
(90) ZEN250 (90 points) ZEN250
(88) CELESTRON C-11
(88) Takahashi FS-152
(88) INTES-MICRO ALTER-7N
(86) AOK K150/3000 Zerodur
(86) Orion 250cmF6.3
(85) Takahashi TOA-130F
(84) TMB 130mm/F9.25-LW
(84) Zeiss APQ130
(84) TEC-140 (84 points)
(83) AP SFX130EDT 130mmF7.8
(83) AP 140EDF4 140mmF7.5 (83 points)
(83) ASTOROSIB 250RC
(82) Zeiss MENISCAS180
(80) Vixen VMC260L
(77) Takahashiμ-210
(76) AP 130EDFGT 130mmF6.3
(75) TeleVue NP127
(75) INTES-MICRO ALTER-607
(75) INTES MN-61
(74) Takahashiμ-180
(73} INTES-MICRO ALTER-7

[maknewtnut]

Thus far, IMHO Barnett has the best grasp of these discussions. First is this Mr Yoshida is another amateur astronomer, just like all of us. Because of that, there's no reason for anyone to take offense to their favorite scope either not making the list or others scoring higher.

With that said, he does seem to be experienced as well as formulating a program in an effort to remain as true to the scientific method as one can expect from empirical observation.

The Intes Micro 608 is a 150mm f/8 ED doublet refractor, not a reflector or catadioptric design. I don't recall for sure, but would not be surprised if the 7N is a Newtonian. Most folks aren't aware that IM has also produced(and still does with some items) some incredibly good parabaloids, refractor objectives, Ritchey-Chretiens, and more.

The Asian market has known this for some time. Thus far, N American residents still seem to be caught up in the refractor craze that began several years ago. That's just fine, and I love a well corrected refractor as much as the next guy, but....

....if you haven't observed with a quality scope of any aperture over 6", take some time at this year's upcoming star parties to take a look for yourself.

Heck, I question why the FS152 is rated so high given the level of CA that creeps into these fluorite doublets at even 5", but that just goes to show there is still subjectivity involved in any empirical observation study. Mileage will definitely vary, which is also proven by Steve's comments. I sold my TEC140 after several sessions with it and an MN76 side by side. I've used many M715's as well, and draw a different conclusion than Steve there as well.

This is one person's findings, period. I'm surprised there isn't more ruckus about a couple of 130mm ranking higher than a few of the 140's. Another is seeing a 6" MakNewt score the same as an NP127. Whether ratings lists, ratings websites, or discussion groups such as CN; it might be wise to look more for trends that one person's opinion. Each person will come away with different points that caught their attention. It's probably pretty obvious what caught my attention, but still, it must be taken in perspective.

[SteveC]

Well, shame on Intes Micro for confusing me. Do you think they could introduce a little diversity in their scope nomenclature so that models don't appear all discombobulated? I thought that nonsense ended with the end to the cold war.

Thanks for straightening all that out.

Btw, the IM 715 is equal on the planets with the TEC140 when the scope reaches ambient air temp. That's not too often when temp is dropping, where I live.

[maknewtnut]

After a brief Google search, I believe there's a good chance the Alter 7 and 7N are not IM's nomenclature, but the way in which Kasai Trading markets the M703 and MN76. If that is the case, then Yoshida must be 100% accurate. ;*)

[Fomalhaut]

This is one person's findings, period.

As far as I've read Mr. Yoshida doesn't do his evaluations alone, but together with astro-pals.

Chris

[Scruffy]

The modern telescope is mechanically and optically complex.

The variables are near infinite and we could all just rattle off a few dozen. Just like cars, if you take any of the tested scopes and let the manufacture tweek them the rankings would change depending on exactly what the reviewer was looking for.

Interesting list. However, I wouldn't trust any one person to create such a definitive list that it could be reproduced bay others down to the last detail. (Kind of like the scientific method.)

Its a list. Mr. Y did a great job. Its just one datum in a world of data.

We all make our own decisions just like we make our own choice of what beauty is. Just think of how screwed up the world would be if everyone agreed on who was beautiful and who was not. Gladly, that will never happen. Neither will there ever be a definitively list that can't be questioned for method, criteria, assumptions, weightings, #of samples, etc. etc. etc.

[Tamiji Homma]

This is one person's findings, period.

As far as I've read Mr. Yoshida doesn't do his evaluations alone, but together with astro-pals.

Chris

Hi Chris,

To my understanding after I talked to him, this list is his. He may have observed with his astro buddies together but evaluation is just his.

However, when he has a doubt, he consults his friend who has optical bench to confirm/verify his findings.

Some case, when a scope happens to be an obvious lemon, he does not include it in his ranking list.

Tammy