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Svbony FPL 51 102ED doublet versus WO FLT 91 APO Triplet

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#1 Paul AZ

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Posted 22 May 2022 - 09:07 PM

I currently own several telescopes ranging from SCT 9.25 and 8 inch to a couple refractors and even a 127 mm Mak Cass.

 

Lately I’ve been watching videos regarding the Williams optic FLT 91 APO and the Sharpstar  94 EDPH and even different variations of the 115 APO refractor telescope and I wonder if I should upgrade from my current Svbony 102ED doublet telescope to a triplet.

 

I got a really good deal on the Svbony 102ED and  I’m trying to understand if it’s worth potentially an extra $1,000 to $1500 or more to upgrade to an APO triplet. Is there really that much of a difference? I just took out my 102ED and mounted it to look at some daytime objects and using a 3.5 mm Pentax eyepiece and even a “TMB” 2.5 mm planetary eyepiece I find it difficult to see any visually measurable chromatic aberration when the object is focused. The objects I am looking at are palm trees at the trunk and the limbs with a bright background blue sky and rooftop tiles with bright sun hitting them and when the object is focused I find it difficult to see any chromatic aberration or purple fringing. I know it has to be there since I am using an ED doublet but it is hard to see. So this was at power of  280x.

 

I have also gone onto Astrobin and searched for photographs using various APO telescopes and just not sure I can see a difference visually. However, I must admit that there is a desire to be able to claim that my astro photos are taken with a higher end APO telescope. 😁🤓 It is sort of like driving a Camero or some other “kind of” sports car when I’d rather be seen in a nice new Corvette.  😂

 

I have photos in my gallery which I took with the 102 ED and Mead DSI IV. I still need to master exposure times to prevent star bloating etc but could I really expect that big of a difference to justify investing in an APO like a WO FLT 91?


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#2 vidrazor

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Posted 22 May 2022 - 09:51 PM

The WO uses better glass, but the SVBONY is longer, and the FL minimizes the difference in the glass to a degree. The WO has a lot of bells and whistles and is a nice scope, albeit at $2000. The SVBONY is $600, but well basically equipped.

 

It depends whether you want to spend the money or not. The SVBONY scopes are pretty decent scopes, especially for their price. Just use it as you intend to and see if it works for you or not, as you already have it.


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#3 Paul AZ

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Posted 22 May 2022 - 11:19 PM

The WO uses better glass, but the SVBONY is longer, and the FL minimizes the difference in the glass to a degree. The WO has a lot of bells and whistles and is a nice scope, albeit at $2000. The SVBONY is $600, but well basically equipped.

 

It depends whether you want to spend the money or not. The SVBONY scopes are pretty decent scopes, especially for their price. Just use it as you intend to and see if it works for you or not, as you already have it.

Good point regarding the focal length. What is also confusing or concerning is the potential to spend the money and then not see any difference visually or photographically. Especially after reading some reviews where others have had issues with some APO’s including the WO and Sharpstar 94 and others. That is what gives me concern and hesitation to make that investment. I guess I could order one and if I don’t see the benefit still return and take the restocking hit. 
 

When I recently purchased the Touptek 2600 the improvement compared to the Meade DSI iv was obvious, so it was money well spent.



#4 vidrazor

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Posted 22 May 2022 - 11:36 PM

Good point regarding the focal length. What is also confusing or concerning is the potential to spend the money and then not see any difference visually or photographically. Especially after reading some reviews where others have had issues with some APO’s including the WO and Sharpstar 94 and others. That is what gives me concern and hesitation to make that investment. I guess I could order one and if I don’t see the benefit still return and take the restocking hit. 
When I recently purchased the Touptek 2600 the improvement compared to the Meade DSI iv was obvious, so it was money well spent.

Are you working with the Touptek 2600 on an ASCOM based system, or on Ekos? I've been looking at Touptek cams (not the 2600) for my Ekos setup.
 



#5 Paul AZ

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Posted 23 May 2022 - 12:54 AM

Are you working with the Touptek 2600 on an ASCOM based system, or on Ekos? I've been looking at Touptek cams (not the 2600) for my Ekos setup.
 

Hello, I am using the Toupsky software that came with it but will be trying out NINA soon.

 

I did get back out this evening and looked at some stars using high magnification with my Svbony 102ED and also looked at my earlier single unstacked images and I don’t see any CA so I don’t see myself buying a triplet unless I decide to get something larger like 130mm refractor. Then again if I can find a 130mm ED doublet then I’d go that route.



#6 licho52

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Posted 23 May 2022 - 09:06 PM

For AP you could fit the Grand Canyon between these 2.  For visual I have no idea.


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#7 Paul AZ

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Posted 24 May 2022 - 02:12 AM

For AP you could fit the Grand Canyon between these 2.  For visual I have no idea.

I am still thinking about it. I’ll probably go for an APO soon but not sure which one. I’d like to go a bit larger and can always use that .63 reducer to go wider if needed.


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#8 Jim in PA

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Posted 24 May 2022 - 02:19 AM

I am still thinking about it. I’ll probably go for an APO soon but not sure which one. I’d like to go a bit larger and can always use that .63 reducer to go wider if needed.

I'm right there with you, Paul.  You've done some great work with the Svbony 102 and DSI IV.  I still haven't finished one target yet this year with mine lol.gif

 

But I'm wondering if I might be better off with a triplet.  Or should I wait awhile and just get some more time with the ED 102?  I also have the same concerns after hearing about some of the problems people have had with triplets.  Which one to roll the dice on, and will it make a marked improvement over the Svbony 102ED?  Wish I knew.  I'm looking at 80mm's, though...maybe I should be looking at a bigger frac?  Still on the fence.

 

Best of luck and keep us posted!   Jim


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#9 Paul AZ

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Posted 24 May 2022 - 02:31 AM

Hi Jim, yes I think I will run some simple shots in the next night or without any filters and see if I can detect enough CA that it bothers me. One scope I have been looking at is the Astrotech 115 EdT and other variants. For less than the WO FLT91 I can get a bit more aperture for my money in a triplet. The WO does look nice though.


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#10 Jim in PA

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Posted 24 May 2022 - 03:32 AM

I was thinking the same thing lol.gif   I was looking at the AT72EDII, then the AT80EDT...why not the 115 EDT?  I can feel the "new scope" excitement coming on, and will probably go with AT...although I'm intrigued by the TS-Optics triplets...just not as easy to get on this side of the pond.  I've not looked much at the WO, perhaps some more perusing is in order.  CS, Jim


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#11 blr

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Posted 24 May 2022 - 05:55 AM

The 102 ED is surprisingly well CA-corrected for being only a FPL51 doublet. For visual, you may see some slight improvement going to a FPL53 triplet, only on the brightest of objects at higher magnifications. It's not worth IMO.

For AP, the difference would be somewhat more pronounced, but again not huge. Do you have problems with CA in your images? Also, as you pointed out, overexposure increases the amount of visible fringing around bright objects, so working with exposure is well worth it in this regard. Post processing can also remove much of the fringing. I'd say, a properly exposed and processed image from the 102 ED may, at the end, show less CA, than one from the triplet.


Edited by blr, 24 May 2022 - 05:56 AM.

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#12 Jim in PA

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Posted 24 May 2022 - 06:31 AM

Paul's images in his gallery are amazing.  Both with the Svbony 70mm ED and Svbony 102mm ED.  I can see no CA issues in those images.  Perhaps I just don't have a good enough eye for such things, but it kind of mirrors my experience with the 102, visually.  I don't have enough AP data yet to come up with images like Paul's.  Mostly a sky issue where I am, but we're getting close to the time of year for decent transparency and imaging.

 

There's something about this scope.  I've never seen anything quite like what it does.  That being said, I've never looked through a large aperture Tak or like scope with no detectable CA.  But what happens with my Svbony 102, is I can see an almost pronounced amount of CA just on either side of focus.  This is normal, but it seems more prevalent in this scope. Like it's more intense.  But as I approach focus, it kind of "snaps" and I can see the CA merge down into the image and disappear at focus.  I do see some CA on the upper limb of the moon at high mag, but I haven't yet found an actual star that has any color fringing at focus.  Which makes me wonder if I will ever have CA problems with this scope for wide-field DSO AP.  It seems like I won't.  And looking at Paul's images just confirms that for me.

 

I still think a good triplet and a cooled camera (I use DSLR's for DSO's) are in my future as some of the images I've seen taken with that type of equipment are astounding.  I just wonder if it's the right time or if I should spend a year or two with the ED doublet first.  I'm not at the level Paul has demonstrated yet, but have been having the same thoughts about triplets.


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#13 blr

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Posted 24 May 2022 - 07:21 AM

I just looked at the images in Paul's gallery and I'll second Jim's opinion above. I don't see any issues with CA, great images. I can't see any reason to spend $2000 on a new scope. Well, GAS is a huge driving force, as we all know...

These 102/7 ED refractors are really amazing for the money!


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#14 Paul AZ

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Posted 24 May 2022 - 07:27 AM

Lots of great input. I am definitely going to do some more pixel peeking with what I have without filters and with and see how they look. In the pics I took and posted, all were with the duo narrowband filter so not sure if that could have prevented any CA from showing up in the photos as a result of the wavelengths that are blocked. Thanks for you input.


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#15 vidrazor

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Posted 24 May 2022 - 02:02 PM

Lots of great input. I am definitely going to do some more pixel peeking with what I have without filters and with and see how they look. In the pics I took and posted, all were with the duo narrowband filter so not sure if that could have prevented any CA from showing up in the photos as a result of the wavelengths that are blocked. Thanks for you input.

Honestly I think you're overthinking this, just shoot with it. I saw the pic of your scope with the Meade right angle attachment, I hope you're not shooting through that.


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#16 Paul AZ

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Posted 24 May 2022 - 03:25 PM

Honestly I think you're overthinking this, just shoot with it. I saw the pic of your scope with the Meade right angle attachment, I hope you're not shooting through that.

Oh my ha ha no I am not. That was only for visual use . You are right though that I am overthinking this and even to the point that I have a stomach ache thinking about how the heck I would justify the expense if my wife is not able to see any difference. She’ll be pretty mad at me. I will do some imaging this week or weekend and then decide. It has been several months since I have been outside imaging that I have forgotten some things and don’t recall and cannot find any examples where I saw any CA even without the filter. I may have deleted the ones without the filter because of the horrible light pollution. I live under Bortle 7/8 skies here in Glendale AZ unfortunately.  



#17 Paul AZ

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Posted 24 May 2022 - 04:26 PM

So I had a short work break WFH still since 3/2020.  I set up my 70ED and found an artificial star, sort of, and took a pic with it pretty much in focus and then out of focus. Not much purple when in focus but plenty when out of focus. I was using an 8mm eyepiece so around 52x mag and the artificial star is blindingly bright visually.

 

 

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#18 Paul AZ

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Posted 24 May 2022 - 04:27 PM

So I had a short work break WFH still since 3/2020.  I set up my 70ED and found an artificial star, sort of, and took a pic with it pretty much in focus and then out of focus. Not much purple when in focus but plenty when out of focus. I was using an 8mm eyepiece so around 52x mag and the artificial star is blindingly bright visually.

Here is out of focus image and no filter is being used. Took pics with iphone 11.

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#19 vidrazor

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Posted 24 May 2022 - 06:03 PM

You're fine dude, don't worry about it, enjoy the scope, it's a good scope.


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#20 Paul AZ

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Posted 25 May 2022 - 01:39 PM

Paul's images in his gallery are amazing.  Both with the Svbony 70mm ED and Svbony 102mm ED.  I can see no CA issues in those images.  Perhaps I just don't have a good enough eye for such things, but it kind of mirrors my experience with the 102, visually.  I don't have enough AP data yet to come up with images like Paul's.  Mostly a sky issue where I am, but we're getting close to the time of year for decent transparency and imaging.

 

There's something about this scope.  I've never seen anything quite like what it does.  That being said, I've never looked through a large aperture Tak or like scope with no detectable CA.  But what happens with my Svbony 102, is I can see an almost pronounced amount of CA just on either side of focus.  This is normal, but it seems more prevalent in this scope. Like it's more intense.  But as I approach focus, it kind of "snaps" and I can see the CA merge down into the image and disappear at focus.  I do see some CA on the upper limb of the moon at high mag, but I haven't yet found an actual star that has any color fringing at focus.  Which makes me wonder if I will ever have CA problems with this scope for wide-field DSO AP.  It seems like I won't.  And looking at Paul's images just confirms that for me.

 

I still think a good triplet and a cooled camera (I use DSLR's for DSO's) are in my future as some of the images I've seen taken with that type of equipment are astounding.  I just wonder if it's the right time or if I should spend a year or two with the ED doublet first.  I'm not at the level Paul has demonstrated yet, but have been having the same thoughts about triplets.

Well I did it. I ordered the WO FLT 91 along with the reducer. I also looked at the TS 90mm APO that uses fpl55 glass and with the current exchange rates and import tax going with WO is a bit more but I would rather deal with a company with local presence and I’ll be keeping this for many years.


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#21 Paul AZ

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Posted 25 May 2022 - 02:40 PM

I just looked at the images in Paul's gallery and I'll second Jim's opinion above. I don't see any issues with CA, great images. I can't see any reason to spend $2000 on a new scope. Well, GAS is a huge driving force, as we all know...

These 102/7 ED refractors are really amazing for the money!

OMG ha ha ha I just got this. “Well, GAS is a huge driving force, as we all know...” 

 

With all of the acronyms and the use of all caps I was wondering what you meant. . I ended up taking the plunge after all. The WO should arrive Friday so I’ll have the weekend to play with it.



#22 blr

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Posted 25 May 2022 - 05:13 PM

GAS= Gear Acquisition Syndrome. 

I've been fighting it (for more than one hobby) for the best part of 30 years now.

 

PS: Congrats on your purchase, enjoy it.


Edited by blr, 25 May 2022 - 05:15 PM.

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#23 Paul AZ

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Posted 25 May 2022 - 05:17 PM

GAS= Gear Acquisition Syndrome. 

I've been fighting it (for more than one hobby) for the best part of 30 years now.

 

PS: Congrats on your purchase, enjoy it.

Oh ok I got it.



#24 Tarantular

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Posted 26 May 2022 - 02:30 PM

I am kinda excited to see your results with the new scope Paul ! You have already done amazing work with the SV503, cant wait to see how much more you can improve it. For amateurs like me, this scope is absolutely plenty. I am even thinking of parting away with my good old mak at some point. This is how much more i like the SVBONY.


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#25 vidrazor

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Posted 26 May 2022 - 06:46 PM

I am kinda excited to see your results with the new scope Paul ! You have already done amazing work with the SV503, cant wait to see how much more you can improve it. For amateurs like me, this scope is absolutely plenty. I am even thinking of parting away with my good old mak at some point. This is how much more i like the SVBONY.

Maks are handy for planetary tho.


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