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sva130t vs svx130t

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#1 joelin

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Posted 17 July 2019 - 08:19 PM

Stellarvue has told me they can still make the discontinued SVA130T w/ 2.5" SV focuser at $3295 with the 0.95 strehl test instead of the current SVX130T w/ 3.5" SV focuser at $4995 thats hand figured to 0.98 strehl. 

 

They can also do focuser upgrades, +$300 for the 3.5" SV focuser or $550 for the 3" Feather Touch focuser. 

 

Would you notice a difference between the SVA and SVX for visual and/or imaging? Would you recommend getting one or the other?


Edited by joelin, 17 July 2019 - 08:19 PM.


#2 gezak22

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Posted 17 July 2019 - 08:30 PM

Do the flatteners (and reducers) illuminate a full frame sensor - 43 mm diagonal? Have you seen images of either configuration on astrobin?


Edited by gezak22, 17 July 2019 - 08:31 PM.


#3 ris242

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Posted 17 July 2019 - 10:50 PM

0.95 vs 0.98 for 50% more cost?

hhhhmmmmm



#4 Nippon

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Posted 18 July 2019 - 12:52 AM

My SV 102T is pre SVX and it came with a certified Strehl of 98.8 and it's visual performance is superb.There are a lot of negative opinions about optical test reports. But I've read a lot of posts and classifieds for pre SVX Stellarvue scope owners stating reports coming in above .95 and .95 is really pretty good. As far as imaging I have no experience. It would be a tough call for me wrestling with my desire for the best and trying to avoid spending needless extra money and it is a whole lot of extra money. I trust Stellarvue they claimed there former scopes were excellent and I know mine is. They say the SVX are even better and they probably are but can it be seen visually or in images I don't know. Best thing is to probably just ask Vic. I believe he would be straight with you.


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#5 213Cobra

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Posted 18 July 2019 - 01:22 AM

If the financial delta isn't meaningful to you, get the X. If money matters, however, get the A and don't give it a second thought. The X will be better, even visually but it might take owning the X and having extended experience with it to recognize all of its value. The human brain is a hungry beast, especially when informed by visual input. Whatever it has available to it, it wants more. Your mind's visual acuity will improve to fully realize value in even slight improvements if you give yourself the chance to be exposed to them. It won't if you don't. We're all into diminishing returns on these types of questions. When you can afford it, go for the closer approach to perfection. Your hungry beast brain will catch up and eventually demand even more.

 

Phil



#6 bobhen

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Posted 18 July 2019 - 08:06 AM

If you really want to save some money consider the Telescope Express Photoline 130mm F7 triplet. The scope will have the same optical quality as the SV SVA 130mm BUT the Photoline 130 comes with “better glass”, as it comes with an FPL 53 center element.

 

You can also get one with a 3.7” focuser for $2,250.

 

So your real dollar comparison is between the Photoline 130mm F7 with the 3.7” focuser for $2,400 versus $5,000 for the SV SVX 130mm – around a $2,600 difference.

 

HERE is a link to the Photoline 130mm F7, if interested.

 

If you want the absolute best color correction, consider a Takahashi TOA 130mm with its 2, FPL 53 lens elements.

 

If money were a top priority, I would consider the Photoline 130mm F7. If performance were a top priority, I would consider a Tak TOA 130.

 

Bob


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#7 k5apl

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Posted 18 July 2019 - 08:36 AM

I owned a 102mm refractor from a respected designer and manufacturer......it had a test report of .98 Strehl.  It gave wonderful

views.  Unfortunately I had an accident and the objective was damaged, so it was replaced (with minor cost) by an objective with a .95 Strehl (test report).  I could see a difference, to the extent that I ended up selling the telescope.  I don't know if the difference was the only difference, but that was my experience.  So my choice is always for the higher Strehl ratio.



#8 gezak22

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Posted 18 July 2019 - 08:37 AM

... and if hassle-free imaging is a priority, consider a Televue 127is, though with the reducer it will not cover a full format dslr.



#9 joelin

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Posted 18 July 2019 - 09:46 AM

If you really want to save some money consider the Telescope Express Photoline 130mm F7 triplet. The scope will have the same optical quality as the SV SVA 130mm BUT the Photoline 130 comes with “better glass”, as it comes with an FPL 53 center element.

 

You can also get one with a 3.7” focuser for $2,250.

 

So your real dollar comparison is between the Photoline 130mm F7 with the 3.7” focuser for $2,400 versus $5,000 for the SV SVX 130mm – around a $2,600 difference.

 

HERE is a link to the Photoline 130mm F7, if interested.

 

If you want the absolute best color correction, consider a Takahashi TOA 130mm with its 2, FPL 53 lens elements.

 

If money were a top priority, I would consider the Photoline 130mm F7. If performance were a top priority, I would consider a Tak TOA 130.

 

Bob

does TS guarantee their Photoline series to perform at the 0.98 strehl level with a test report or something else?


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#10 joelin

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Posted 18 July 2019 - 09:49 AM

I owned a 102mm refractor from a respected designer and manufacturer......it had a test report of .98 Strehl.  It gave wonderful

views.  Unfortunately I had an accident and the objective was damaged, so it was replaced (with minor cost) by an objective with a .95 Strehl (test report).  I could see a difference, to the extent that I ended up selling the telescope.  I don't know if the difference was the only difference, but that was my experience.  So my choice is always for the higher Strehl ratio.

what manufacturers other than stellarvue have strehl reports that come with their scopes?



#11 bobhen

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Posted 18 July 2019 - 10:40 AM

does TS guarantee their Photoline series to perform at the 0.98 strehl level with a test report or something else?

The Astro-Tech 130mm (which is around $1,900) the SV SVA (pre SVX) 130mm and the TS Photoline 130mm are all imported from China and generally have the same mid 90s Strehl quality. The TS Photoline version has better glass with the FPL 53 element.

 

TS has the facilities for testing. I believe that test reports are available for additional cost or are in some cases included.

 

If interested, contact Telescope Service and ask them.

 

If you want better than any of the above from any manufacturer, you will, of course, have to pay a lot more.

 

Bob



#12 bobhen

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Posted 18 July 2019 - 10:48 AM

what manufacturers other than stellarvue have strehl reports that come with their scopes?

You might want to read THIS essay by Roland Christen of Astro-Physics regarding optical testing.

 

Bob


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#13 ArkabPriorSol

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Posted 18 July 2019 - 10:59 AM

Strehl ratings are more snake oil marketing terms than realistic optics qualifiers. The difference between a strehl of 0.95 and 0.98 is so incredibly small I believe no human eye could tell the difference in a double blind test. The whole thing reminds me of audiophiles claiming they can get the difference between 16bit and 24bit audio. 

 

Furthermore, the strehl rating that the Stellarvue report provides is a monochromatic strehl rating, meaning that claimed 98% of light accuracy only applies to a narrow color band (probably green). Search CloudyNights for discussions of monochromatic strehl vs. polychromatic strehl. 

 

But at the end of the day if that marketing term makes you feel better for bragging rights, then maybe it's worth it. 

 

I think what's far more important when comparing the SVA vs SVX is the quality of the focuser and resale value of the scope. The larger focuser is very important for imaging purposes, and the FeatherTouch option is incredibly enjoyable to use for visual too. I suspect the SVX will depreciate it's resale value faster than the SVA. 

 

For what it's worth I just purchased a used Takahashi TOA-130 with a 3.5" FeatherTouch for $4.5K. It will not depreciate at all, I will probably be able to resell it at the same value years from now. 


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#14 Nippon

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Posted 18 July 2019 - 11:05 AM

Not many provide test reports and I think for some good reasons. The main one being that the information in the report is really only useful to the optician making the lens. And then there is say you buy a scope that has a report with a higher Strehl than the company's minimum Strehl. Your observing buddy is so impressed he buys the same scope only his comes with a report right at the minimum Strehl guaranteed by the company. Well your friend feels cheated even though he was not  There are a lot of claims that the pre SVX  Stellarvue triplets are just rebranded and the same as those offered by TS. I don't think that is true. Even if they are only different to the extent that Vic rejects optics and components that don't meet his high standards. That alone has a lot of value but I think it goes beyond that to the point that Vic orders components to his specification which may well include the objective design itself and builds some components at his own facility. Neither the former SVA or the current SVX advertise FPL53, to my knowledge, but I think the reason is the objective is one of Vic's own designs and weather it was sourced out or built in house, and I think the 130 objectives have always been made in house, I think it is a design that Vic wants to use because it performs well. 


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#15 gezak22

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Posted 18 July 2019 - 11:23 AM

And since Joe complained about his previous scope not fully illuminating his full frame sensor, perhaps field coverage should be added to the spec list.



#16 ArkabPriorSol

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Posted 18 July 2019 - 11:26 AM

Not many provide test reports and I think for some good reasons. The main one being that the information in the report is really only useful to the optician making the lens. And then there is say you buy a scope that has a report with a higher Strehl than the company's minimum Strehl. Your observing buddy is so impressed he buys the same scope only his comes with a report right at the minimum Strehl guaranteed by the company. Well your friend feels cheated even though he was not  There are a lot of claims that the pre SVX  Stellarvue triplets are just rebranded and the same as those offered by TS. I don't think that is true. Even if they are only different to the extent that Vic rejects optics and components that don't meet his high standards. That alone has a lot of value but I think it goes beyond that to the point that Vic orders components to his specification which may well include the objective design itself and builds some components at his own facility. Neither the former SVA or the current SVX advertise FPL53, to my knowledge, but I think the reason is the objective is one of Vic's own designs and weather it was sourced out or built in house, and I think the 130 objectives have always been made in house, I think it is a design that Vic wants to use because it performs well. 

I think Vic is an honest guy, but he's a business man first and foremost, and he's trying to sell telescopes, keep that in mind. The fact the Stellarvue doesn't advertise the ED glass type indicates that it's probably not an attractive choice of glass. If it was FPL53 or fluorite they would certainly advertise that.



#17 Nippon

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Posted 18 July 2019 - 11:39 AM

As far as the always debated Stellarvue business model goes it will never be resolved. But it boils down to weather any perspective buyer perceives Vic as a businessman first or a telescope maker first. I believe he is first and foremost a telescope maker.  



#18 johnsoda

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Posted 18 July 2019 - 11:39 AM

Here’s a different take on the Strehl Ratio from a very respected expert. 


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#19 Nippon

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Posted 18 July 2019 - 12:06 PM

I've read that one too in fact I've read just about everything on the subject. All of that information can be spun in different ways and frequently is. That is the reason I've come to the conclusion that a company's reputation and any particular scope's actual performance Is the best way to decide. Buy from a company with a good reputation for quality and after sale support and if for some reason the scope you receive is sub par send it back.


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#20 joelin

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Posted 18 July 2019 - 07:17 PM

If you really want to save some money consider the Telescope Express Photoline 130mm F7 triplet. The scope will have the same optical quality as the SV SVA 130mm BUT the Photoline 130 comes with “better glass”, as it comes with an FPL 53 center element.

 

You can also get one with a 3.7” focuser for $2,250.

 

So your real dollar comparison is between the Photoline 130mm F7 with the 3.7” focuser for $2,400 versus $5,000 for the SV SVX 130mm – around a $2,600 difference.

 

HERE is a link to the Photoline 130mm F7, if interested.

 

If you want the absolute best color correction, consider a Takahashi TOA 130mm with its 2, FPL 53 lens elements.

 

If money were a top priority, I would consider the Photoline 130mm F7. If performance were a top priority, I would consider a Tak TOA 130.

 

Bob

 

if 1 strehl is perfection and the stellarvues are at 0.95 to 0.99...how can takahashi's beat them? 



#21 gezak22

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Posted 18 July 2019 - 08:04 PM

if 1 strehl is perfection and the stellarvues are at 0.95 to 0.99...how can takahashi's beat them? 

Quality control. Better uniformity across the field. Larger field coverage.

 

Edit: Better poly strehl, spherochromatism, ...


Edited by gezak22, 18 July 2019 - 08:06 PM.

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#22 ArkabPriorSol

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Posted 18 July 2019 - 09:28 PM

if 1 strehl is perfection and the stellarvues are at 0.95 to 0.99...how can takahashi's beat them?


Takahashi scopes have independently been tested by 3rd parties to exhibit superb polychromatic strehl ratings (>0.98).

But there are far more significant attributes that distinguish a great scope than strehl ratio. Build quality, focuser, tech support, resale value, etc.) I went from having a SVR102 rated at "0.988 strehl" to a Takahashi. The build quality and optics difference of the Tak was very noticeably better. Taks are constructed like tanks. Every detail exudes high quality.

I will say though, that I've had excellent top notch experiences dealing with Stellarvue's support. I love that could call them up at anytime and get Alex or Vic on the phone for expert support on any issue.

So I guess my point is there is much more to the value of a scope then just an insignificant strehl rating. The SVX has a bigger-better focuser and it might be easier to sell on the used market someday. I'd consider those things first when comparing SVA vs SVX vs Takahashi.

#23 stevew

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Posted 18 July 2019 - 09:34 PM

The difference between a strehl of 0.95 and 0.98 is so incredibly small I believe no human eye could tell the difference in a double blind test. The whole thing reminds me of audiophiles claiming they can get the difference between 16bit and 24bit audio. 

 

 

There maybe a few that will be able to tell the difference under perfect viewing conditions, but under the types of sky conditions that many of us have I'm pretty sure most couldn't.

Never the less .95 strehl is an excellent lens in my book.

 

Quite often we can't see the forest for the trees and get too caught up in worrying about these types of things. [Especially in the refractor forums] 

Whether your scope is barely diffraction limited or has a .99 strehl ratio just get out as often as you can and look at these incredible objects in the sky and enjoy what your scope can show you. We are very fortunate to have the luxury of a fine telescope at our disposal to witness the universe in a way that most of the people on the earth never will. 


Edited by stevew, 18 July 2019 - 09:59 PM.

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#24 Nippon

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Posted 18 July 2019 - 09:46 PM

Takahashi scopes have independently been tested by 3rd parties to exhibit superb polychromatic strehl ratings (>0.98).

But there are far more significant attributes that distinguish a great scope than strehl ratio. Build quality, focuser, tech support, resale value, etc.) I went from having a SVR102 rated at "0.988 strehl" to a Takahashi. The build quality and optics difference of the Tak was very noticeably better. Taks are constructed like tanks. Every detail exudes high quality.

I will say though, that I've had excellent top notch experiences dealing with Stellarvue's support. I love that could call them up at anytime and get Alex or Vic on the phone for expert support on any issue.

So I guess my point is there is much more to the value of a scope then just an insignificant strehl rating. The SVX has a bigger-better focuser and it might be easier to sell on the used market someday. I'd consider those things first when comparing SVA vs SVX vs Takahashi.

 

You have two Takahashi scopes listed in your info. When you went from your SVR102 to the Tak, which model Tak was it?



#25 ArkabPriorSol

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Posted 18 July 2019 - 09:57 PM

You have two Takahashi scopes listed in your info. When you went from your SVR102 to the Tak, which model Tak was it?


I sold the SVR102 to buy the FSQ106N for imaging. I could not get a flat field with the SVR102, no matter what I tried. I tried adjusting the spacing with 1mm spacers, I tried a different flattener/reducer, and I even tried sending it back to SV for them to check it out. While slightly improved the field still had elongated stars in the corners. I got the FSQ and the first night out I had perfect stars across the whole field. I recently bought the TOA for visual use and it's build quality is every bit as robust as the FSQ.


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