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Was the Tak Sky 90 a flop?

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#1 CHASLX200

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Posted 20 December 2015 - 08:46 AM

I never see much talk about the Sky 90. Was that model a flop?  Kinda would like to try out a used one one of these days.



#2 rolo

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Posted 20 December 2015 - 09:08 AM

Not sure if  flop is the right word but not many were sold. Personally I don't like the fact that its not a collimatable cell. Kind of an odd size with so many 80mm APO's available. And of course, the price...By the way, the Sky 90 II didn't do any better and have been discontinued...


Edited by rolo, 20 December 2015 - 09:11 AM.

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#3 t.r.

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Posted 20 December 2015 - 09:37 AM

This topic is near and dear to my heart, as I had done a lot of research into this scope years ago, knew well what it would do and wouldn't do, and accepted it for what it was when I made my "educated" purchase. I have defended it when needed and given my opinions on it when asked. I  purchased the scope used and for a three year period, put it through its paces. I'm visual only and have used several other achros and apos from which to compare. The model I had was the NSV SKY II model that had collimation screws.

 

No, the scope is not a flop. To the contrary, in its day, it was quite a feat to packing that much aperture in a very small portable package and deliver the sharp images that it did. Does it show CA...sure. But not to a level that destroyed contrast or mired details that rendered them compromised. Certainly way better than my C80SS f/5 achro which I compared it to. Similar to my C80ED in color correction, but with 10mm better resolution. It also bested a William Optics Megrez 90ED. I used the Sky 90 as grab and go and for travel. I used it primarily for planetary/lunar study and without the corrector designed for it. I used a TV 3-6 zoom for higher mags and never once felt like anything was missing from the detail, residual CA and all. The Tak corrector designed for it was to remove that CA, but I couldn't justify the price of it for what I was already seeing. Others may/will disagree. I was amazed at the detail and contrast put up by the Sky 90 of Jupiter and Mars at 167x. That it could go from low power widefield to planetary so easy was quite an attribute that I enjoyed also.

 

With this said, many thought that the level of color correction wasn't worth the price new. I'd agree...that is why I purchased used! Also, if jostled, the scope would loose collimation, many thought too easily. The fast 5.56 focal ratio would strain the best mechanics to hold alignment extremely well and the Tak needed it or more CA would show. So, there were a few scathing reports, IMHO due to the price and emotion, rather than a clinical view as to what it actually could do. I sold mine only to upgrade to a triplet 92mm with better color correction at less price. That just seemed smart. But the Tak was made to a higher level of quality even with the residual CA. So, in my humble opinion, no, not a flop at all, on the contrary...quite a scope in its day that could still be appreciated with the right owner expectations! ;)  


Edited by t.r., 20 December 2015 - 09:45 AM.

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#4 StarDust1

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Posted 20 December 2015 - 10:06 AM

The Sky90NSV that I had was very sharp and contrasty. 



#5 Paul G

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Posted 20 December 2015 - 10:08 AM

It is a nice scope, but as t.r. says you can get better color correction with a less expensive triplet. When the Sky 90 was first released it was widely thought to be Tak's answer to the no longer available AP Stowaway, but it couldn't match the Stowaway's color correction and speed (f4.9, less than 0.01% focus variation from 650nm to 430nm). The initial units showed pinched optics in cold weather, the same problem the first TOA's had, and the cell was redesigned. Temmon Guide did one of their exhaustive reviews of the scope, I can probably dig out the magazine and scan it if you wish. Someone translated it from Japanese and posted a link on the UncensoredTak group for a while but that link is no longer active. They liked the scope but didn't like the color correction, said the Extender-Q should be a required accessory because it brings the measured color error down to that of the Tak FS series.

 

I've used several and with the Extender-Q it is a very nice scope, but I suspect it fell to the same market forces as the AP Traveler and longer Stowaway, the market was beginning to fill with much less expensive 3-4" scopes from China, and selling a much more expensive alternative was a difficult row to hoe.


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#6 zawijava

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Posted 20 December 2015 - 11:13 AM

Having owned many Takahashi scopes and mounts, I regret saying that the Sky 90 was THE only one I was disappointed with.

Tim
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#7 edif300

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Posted 20 December 2015 - 02:01 PM

Less than 0.01% focus variations were a constant over 30 years in the A-P specifications -beyond 25nm-, no matter if in a f8 or f5 scope. 0.01 has made a long run and beyond that implicitly has an arguable veracity for me.

Seems sure that both, SKY-90 and the AP Stowaway, are not an essentially apo if one compares to a TOA.



#8 Paul G

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Posted 20 December 2015 - 02:46 PM

Less than 0.01% focus variations were a constant over 30 years in the A-P specifications -beyond 25nm-, no matter if in a f8 or f5 scope. 0.01 has made a long run and beyond that implicitly has an arguable veracity for me.

Seems sure that both, SKY-90 and the AP Stowaway, are not an essentially apo if one compares to a TOA.

The TOA isn't f4.9, 6.5 pounds, and 14" long, either.


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#9 jrbarnett

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Posted 20 December 2015 - 03:04 PM

 

Less than 0.01% focus variations were a constant over 30 years in the A-P specifications -beyond 25nm-, no matter if in a f8 or f5 scope. 0.01 has made a long run and beyond that implicitly has an arguable veracity for me.

Seems sure that both, SKY-90 and the AP Stowaway, are not an essentially apo if one compares to a TOA.

The TOA isn't f4.9, 6.5 pounds, and 14" long, either.

 

Heck, the TOA isn't even f/6.3, 18 pounds and 28.5" long, either.  :grin:

 

Do you happen to know what design changes were made as part of the transition from the Sky 90 to the Sky 90 II?

 

The original Sky 90 was NOT an FS-design.  It had a much, much larger air space, which combined with the lack of collimation adjustments, made retaining and restoring proper squaring and centering difficult.  I had a Sky 90 briefly, bought used, out of collimation, and resold in similar condition.  I've never actually seen a Sky 90 II in person, but would be surprised if Takahashi didn't address some of the shortcomings in the original iteration.

 

Regards,

 

Jim


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#10 Paul G

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Posted 20 December 2015 - 03:22 PM

 

 

Less than 0.01% focus variations were a constant over 30 years in the A-P specifications -beyond 25nm-, no matter if in a f8 or f5 scope. 0.01 has made a long run and beyond that implicitly has an arguable veracity for me.

Seems sure that both, SKY-90 and the AP Stowaway, are not an essentially apo if one compares to a TOA.

The TOA isn't f4.9, 6.5 pounds, and 14" long, either.

 

Heck, the TOA isn't even f/6.3, 18 pounds and 28.5" long, either.   :grin:

 

Do you happen to know what design changes were made as part of the transition from the Sky 90 to the Sky 90 II?

 

The original Sky 90 was NOT an FS-design.  It had a much, much larger air space, which combined with the lack of collimation adjustments, made retaining and restoring proper squaring and centering difficult.  I had a Sky 90 briefly, bought used, out of collimation, and resold in similar condition.  I've never actually seen a Sky 90 II in person, but would be surprised if Takahashi didn't address some of the shortcomings in the original iteration.

 

Regards,

 

Jim

 

According to Art Ciampi at TNR in a post on the UncensoredTak group the only difference between the I and the II was the collimation system. The pinching of the optics in cold weather was solved in 2005 with a change in the type of glue used to fix the lens elements in the cell (this info was from a post from Japan, not from TNR so YMMV).


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#11 edif300

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Posted 20 December 2015 - 03:41 PM

Exactly ! ! It's like you said...

Even the AP 130EDT is not an f/5.8 (Traveler).  Both has 0.01 ... 405-650... And here are talking about 0.01 as a semi-Apo  :grin:

 

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#12 samovu

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Posted 20 December 2015 - 05:50 PM

I recently bought a Sky 90 II and it has become my grab and go as well as my travel scope although I've only taken it one one trip to Hawaii so far. I can't speak to the changes or improvements other than to say that for my higher power requirements to see details on planets from my heavily light polluted backyard, this baby works better than my classic FC-76 or FS-78 and is easier to set up than my FS-102. To me it is the sweet spot in terms of getting it outside for a session I may not otherwise have. Oh, and this is with the requisite Extender Q. Without it the image scale, for me, would be too small. 

 

YMMV but it's just right for many of my needs. 

 

Cheers,

John


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#13 gezak22

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Posted 20 December 2015 - 10:03 PM

I too own a Tak Sky 90 II. I've summarized my experience here. In short, when it's collimated and all the accessories are flush (no tilt in optical train) I find the CA to be minimal. Observing the planets is a joy, and the scope is dead simple to transport. If you already own the scope, do yourself a favor and give it an honest shot. However, if you are considering buying the scope, it may be overpriced given its aperture/performance. The TMB92 should be a decent alternative in this form factor.



#14 roadi

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Posted 21 December 2015 - 02:47 AM

I fully agree with all that tr said  ;)

It had its faults as Paul G also pointed out but once solved it was indeed a very nice scope.


Edited by roadi, 21 December 2015 - 02:58 AM.


#15 CHASLX200

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Posted 21 December 2015 - 06:18 AM

I never see many pop up for sale and was thinking of trying one out.  For now i have AT-115mm on order so i will see how it does first.  All of my Taks in the past were first class.



#16 StarDust1

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Posted 21 December 2015 - 07:47 AM

The biggest advantage of the Sky90 is it's portability through it's short focal length. The downside of the short focal length is it can't keep up with an FC100D or FS102 with it's longer focal lengths. With high magnification work it can't keep up with the Tak 4" refractors.

 

It's a beautiful little scope and it has (had) it's place in Takahashi history. It's a scope that you like it or hate it. For its time it was unique.

 

Just a glimpse how small the Sky90 was compared to the FS128, note the Sky90 dew shield in this photo was retracted. 

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#17 t.r.

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Posted 21 December 2015 - 08:45 AM

And it was that "smallness", in a very svelt, compact package, that was really the main selling point of the scope and its best feature. I have always been impressed with optics in miniature form. TV-60, FS-60, Sky-90, TMB-92, WO Megrez-90...the AP Stowaway and TEC110! :bow:  Trying to combine the largest aperture into the smallest package has always been the challenge for scope makers. The original short tube scope, a Vixen made 80mm achromat at f/5, was the very first to do so. The Takahashi went a step further and crammed 10 more mm into the same form factor and improved color correction using fluorite, but did leave a little CA...YES, my Sky 90 fit into the same tight travel case of my C80SS. When put side by side, they even looked the same! That is what Takahashi accomplished back in the day...and has been torn up in the reviews ever since, for doing. :smirk:  


Edited by t.r., 21 December 2015 - 09:15 AM.

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#18 northpole

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Posted 21 December 2015 - 09:06 AM

I love my Sky 90, along with the essential (I feel) extender Q. I bought mine in 2000 or 2001. It's one of the earlier models. Collimation has always been bang on, and this little gem has done a lot of travelling in a Lowepro camera backpack. Around the time when I got this, options for a good travel scope were limited (although my name came up for a Stowaway two months after I bought the Sky90 ). Yes there are cheaper decent alternatives on the market now, but mine won't be on the market anytime soon. 

 

Andre

5460284-telescopes 015e.jpg

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#19 Erik Bakker

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Posted 21 December 2015 - 10:58 AM

What a beauty it is!


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#20 Nuphy

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Posted 22 December 2015 - 11:01 AM

I use my Sky-90 the most of all scopes. It is the newer version, which does not have the pinched optics in cold weather. The views are very crisp (I have the extender-Q) and the size is just right. My TSA-102, FC-76, FCT-76, ... won't get used that much.


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#21 KaStern

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Posted 22 December 2015 - 12:02 PM

Hello CHASLX200,

 

I have seen one wich had been imported from a store in the US by the owner.

It did show deformed stars due to severe decentering. The views through it were quite disappointing.

Later I heared that the scope had been fixed and showed round stars,

but I never got a second look through this sample.

 

Cheers, Karsten



#22 JJK

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Posted 22 December 2015 - 12:25 PM

I've used a friend's Sky 90 coupled with an original Coronado H-alpha solar filter/etalon, and the results were stunning.



#23 NedM

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Posted 28 July 2016 - 09:13 PM

I loved my Sky 90 II, it was a great little scope. Did it show some color? Yes some, but not that much. Did it have field curvature? Yup, however when mated with the extender-q it behaved like an f/8.8, fluorite doublet...not to shabby!
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#24 Bill Barlow

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Posted 29 July 2016 - 09:59 AM

I never see many pop up for sale and was thinking of trying one out.  For now i have AT-115mm on order so i will see how it does first.  All of my Taks in the past were first class.

Are you still going to get the FC100DF?

 

Bill



#25 CHASLX200

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Posted 29 July 2016 - 05:26 PM

 

I never see many pop up for sale and was thinking of trying one out.  For now i have AT-115mm on order so i will see how it does first.  All of my Taks in the past were first class.

Are you still going to get the FC100DF?

 

Bill

 

If the ship ever come in. Waiting for weeks and have no clue why it is taking so long.


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