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KUO 70mm BT's vs Oberwerk BT-70XL-ED

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#1 wrighty338

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Posted 18 August 2022 - 08:27 AM

Following on from Fiske's Best 70mm for astronomy and me looking to replace my 25x100 with something better probably in the mid size range there are 2 obvious front runners that being the widely distributed 70mm BT's under various brands ES/APM/Sky rover and the Oberwerk XL (in grey of course)

82 or 100 BT's are currently not in the running here (i know which ones id buy if i has the money lol) Id like to start with a 70. I believe a 70 will go down to 15x and up to 50x according to ES site - sounds good to me..may aswell take a right first time approach and get into the BT ecosystem?

 

Firstly I can see why Fiske went with BT-70XL-ED, it ships from the same country, great product & service and piece of mind due to this but i didn't see that he considered the "SD Apo" options so im just wondering about the specs between the two confused1.gif

 

My local shop has the basic ES BT 70 for £1035 - id probably spend a little more if its worth it

The Sky Rover and APM "SD apo" options are slightly more from China or Germany. Im UK based so would be importing regardless. From reading last night i found:

 

APM 70 mm 45° SD Apo Binocular, with UF 18  max. 4° FOV 2 Element Air spaced FCD Apochromat (rear lens FCD100 Glass) 400mm Focal 4.5kg

or

Basically the same from sky rover with UF18's but i notice in the description "Optics: double separation achromatic objective lens, including one pice of super ED glass made in Japan" 3.7kg

 

APM or Sky rover with 18mm EPS = £1480 or £1366 + shipping+import+duty+VAT

 

Oberwerk BT-70XL-ED 70mm FK-61 ED objectives, 24mm of clear prism aperture 3.7kg<< this is all i can see and would be £1250 +shipping+import+duty+VAT but is this going to match or exceed the apm "sd apo" 

 

Is the APM weighing more as it has better equipment in there? (Jurassic park reference grin.gif)  I read another post on here where the user thought the sd apo offering was 27-28mm of clear prism vs oberwerks 24mm - not sure how true that is or if it should influence a decision?

 

TL:DR 25x100 will be eaten up to go into BT70 but can anyone shed insight on the oberwerk optics to help me decide which is the superior optic? Thanks for reading

 

Jon


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#2 Fiske

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Posted 18 August 2022 - 08:33 AM

Ordering Oberwerk from the UK seems a little problematic to me, Jon. wink.gif OTOH, I have a lot(!) of skepticism about the reliability of APM shipping, handling, and customer service. Based on my own experiences with them, as well as those of others who have reported their trials and travails in this forum. 

 

scared.gif

 

Sky Rover seems like a decent option, but I'm not familiar with distribution/resellers suitable for Europe and the UK, of course.

 

Good luck with your BT adventure! waytogo.gif


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#3 jrazz

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Posted 18 August 2022 - 08:39 AM

Not Luna Pearl? shocked.gif  Shame... grin.gif

 

 

Anyway, since you're in Europe I would highly recommend going the SD-apo route. Both Fiske and I feel that it's a shame Kevin doesn't sell a "SD" version of the 70XL but he believes there's no market for it here and he's probably right. Everyone wants bigger. I digress, I highly recommend getting the best quality optics you can afford over aperture unless you have really dark skies. I mean, if you can afford the Kowa Highlander or Borg...

 

The Oberwerk 70XL would be a significant step up from the 25x100 but given the choice I'd much rather have the SD-apo. (so yes, the APM SD-apo should perform noticeably better than the OB 70XL or the other FK61 ED BTs)

 

 

Don't forget, eyepieces matter a whole lot as well. Though you can start with the included bundle, getting a good 24mm wide field and a 10mm high quality pair should be high on your list.


Edited by jrazz, 18 August 2022 - 08:42 AM.

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#4 wrighty338

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Posted 18 August 2022 - 09:26 AM

Ordering Oberwerk from the UK seems a little problematic to me, Jon. wink.gif OTOH, I have a lot(!) of skepticism about the reliability of APM shipping, handling, and customer service. Based on my own experiences with them, as well as those of others who have reported their trials and travails in this forum. 

 

scared.gif

 

Sky Rover seems like a decent option, but I'm not familiar with distribution/resellers suitable for Europe and the UK, of course.

 

Good luck with your BT adventure! waytogo.gif

No "problem" as such Fiske, just expensive with the weak pound vs the dollar and all the costs added up together. All options would be from another country near or far, USA, Germany or China. I hear what you're saying though - there is a risk any package could take a bump on its way etc



#5 wrighty338

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Posted 18 August 2022 - 09:34 AM

Not Luna Pearl? shocked.gif  Shame... grin.gif

 

Anyway, since you're in Europe I would highly recommend going the SD-apo route. Both Fiske and I feel that it's a shame Kevin doesn't sell a "SD" version of the 70XL but he believes there's no market for it here and he's probably right. Everyone wants bigger. I digress, I highly recommend getting the best quality optics you can afford over aperture unless you have really dark skies. I mean, if you can afford the Kowa Highlander or Borg...

 

The Oberwerk 70XL would be a significant step up from the 25x100 but given the choice I'd much rather have the SD-apo. (so yes, the APM SD-apo should perform noticeably better than the OB 70XL or the other FK61 ED BTs)

 

Don't forget, eyepieces matter a whole lot as well. Though you can start with the included bundle, getting a good 24mm wide field and a 10mm high quality pair should be high on your list.

Thanks Jordan. so we think the APM/Sky rover will be the better performer - its not just marketing nonsense tongue2.gif

 

You're right its not all about size, the eyepiece's i need a little more homework on but if they can be used on multiple applications in the future im ok with that....like when the 82 or 100 BT itch needs scratching lol.gif



#6 jrazz

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Posted 18 August 2022 - 09:47 AM

I do. 

For me the draw of optics for forever has been the clarity and quality of the view. Growing up I had glasses and until I had LASIK the world was always fuzzy without glasses. Looking through binoculars I felt I didn't need glasses at all so I still look for that sharpness.

 

I can tell the difference between SD and ED and while both are usable the view from my 100XL-SD is so engaging I think it was well worth the $500 premium I paid.

 

 

A word about eyepieces. I found that quality is more important than quantity here. With a telescope I seem to be switching eyepieces in and out constantly. I hardly ever do so with the BT. It's a combination of it being more work, the collimation issues one encounters trying to align eyepieces and the fact that binoculars tend to move more when changing eps. I know the ability to change magnification is a big selling point but really the optical quality is where BTs are at. I am a huge fan of the Pentax lineup but whatever you choose, think about one pair and get the best you can. 


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#7 wrighty338

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Posted 18 August 2022 - 10:07 AM

Certainly will be reading up more on eyepieces, one of the draw's of the 70mm is to be able to get down to 15x (or close to it) i really want to experience that bright wide field for starters

 

I only lost 4-5 hours on here last night lol.gif

 

i think im with you on the draw of quality and clarity 100%, i still feel im at the start of a long adventure 



#8 jrazz

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Posted 18 August 2022 - 10:10 AM

lol.gif lol.gif lol.gif

 

Yeah... This can get deep though if it's any consolation I think you're exactly on the right track.


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#9 Rich V.

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Posted 18 August 2022 - 10:25 AM

From the Explore Scientific US website, their BT 70 SF is the achromat version of the KUO BT; I'd opt for the SD version as sold by APM, whatever the price difference may be.  The SD glass will show finer star points without the colored fringes that achromats cause because they don't focus all the colors of the spectrum to the same exact point.  Well worth it if you want to get the most out of the binos.

 

The difference between the KUO-sourced "27mm" prism aperture BTs like the APM/ Sky Rover and the "24mm prism" like the Oberwerk is only seen with the widest FOV (largest diameter field stop) eyepieces like the 24mm Panoptic which, not coincidentally, also has a 27mm field stop.  A 27mm prism aperture in front of a 27mm FS eyepiece is a good match regarding fullest illumination of the FOV.  A 24mm prism may show a bit of vignette at the edges of the field as it isn't fully illuminating the eyepiece.  It won't cut out any of the FOV, but it may likely darken the image approaching the edge of the FOV.  With eyepieces that have smaller field stops than 24mm, this matter becomes a moot point. 

 

Don't skimp on the mount you're putting the binos on; buy once and enjoy forever.

 

Rich

 

 

 

 

 

 

 


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#10 wrighty338

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Posted 18 August 2022 - 11:47 AM

From the Explore Scientific US website, their BT 70 SF is the achromat version of the KUO BT; I'd opt for the SD version as sold by APM, whatever the price difference may be.  The SD glass will show finer star points without the colored fringes that achromats cause because they don't focus all the colors of the spectrum to the same exact point.  Well worth it if you want to get the most out of the binos.

 

The difference between the KUO-sourced "27mm" prism aperture BTs like the APM/ Sky Rover and the "24mm prism" like the Oberwerk is only seen with the widest FOV (largest diameter field stop) eyepieces like the 24mm Panoptic which, not coincidentally, also has a 27mm field stop.  A 27mm prism aperture in front of a 27mm FS eyepiece is a good match regarding fullest illumination of the FOV.  A 24mm prism may show a bit of vignette at the edges of the field as it isn't fully illuminating the eyepiece.  It won't cut out any of the FOV, but it may likely darken the image approaching the edge of the FOV.  With eyepieces that have smaller field stops than 24mm, this matter becomes a moot point. 

 

Don't skimp on the mount you're putting the binos on; buy once and enjoy forever.

 

Rich

Rich, thanks so much. This is the exactly the kind of info i need. That was my thinking - spend the couple hundred extra for the SD APO if it was better.



#11 ckwastro

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Posted 18 August 2022 - 05:53 PM

Not Luna Pearl? shocked.gif  Shame... grin.gif

 

I must be one of the few who also prefers the battleship gray with the red accents over the Luna Pearl. Not sure why, but I do. Definitely in the minority from everything I’ve read in the bino forum. 


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#12 MT4

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Posted 18 August 2022 - 08:40 PM

I must be one of the few who also prefers the battleship gray with the red accents over the Luna Pearl. Not sure why, but I do. Definitely in the minority from everything I’ve read in the bino forum. 

 

Perhaps I am also in the minority as I think that Luna Pearl is a bit too shiny.  I prefer my Kowa Highlander Prominar's less shiny white with red and dark gray accents.

 

It's a matter of personal taste of course.

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#13 jrazz

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Posted 18 August 2022 - 09:12 PM

That binocular is the only possible exception to my pearl white obsession. Though the shot you had with the blue background made it look even more dope.


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#14 MT4

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Posted 18 August 2022 - 09:20 PM

That binocular is the only possible exception to my pearl white obsession. Though the shot you had with the blue background made it look even more dope.

 

This one right?  smile.gif

 

Comparing the two shots with the actual Kowa, the one with the blue background is actually much closer to how the real thing looks and agree it looks even better.  You have good taste Jordan smile.gif

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Edited by MT4, 18 August 2022 - 09:23 PM.

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#15 jrazz

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Posted 18 August 2022 - 09:22 PM

Yup :)


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#16 range88

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Posted 18 August 2022 - 09:24 PM

SD APO version is always the right answer, especially for 70 aperture price wise.


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#17 ckwastro

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Posted 18 August 2022 - 10:04 PM

Perhaps I am also in the minority as I think that Luna Pearl is a bit too shiny.  I prefer my Kowa Highlander Prominar's less shiny white with red and dark gray accents.

 

It's a matter of personal taste of course.

Dang, I have been eyeballing the Kowas for a while. These pics are making resistance futile! 


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#18 ihf

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Posted 18 August 2022 - 10:48 PM

SD APO version is always the right answer, especially for 70 aperture price wise.

Do you know if there really still are three versions of the 70mm SkyRover made? doublet SA/achromat, doublet SD/FCD100 and ED/??? ?

What is the glass in the ED or is it the same as SD?



#19 jrazz

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Posted 18 August 2022 - 11:12 PM

Generally speaking SD/APO/FCD100 is better/more desirable than ED/FK61. 

 

Case in point:

The Oberwerk BT-100XL ED uses FK-61 objectives and costs $2.5k while the BT-100XL-SD uses FCD100 objectives and costs $3k. According to those that have looked through both the SD version is noticeably better. 

 

 

So the hierarchy goes like this:

SA < ED(FK61) < SD/APO(FCD100) < Fluorite

 

Basically going from left to right you get lower and lower dispersion.


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#20 range88

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Posted 19 August 2022 - 01:44 AM

Do you know if there really still are three versions of the 70mm SkyRover made? doublet SA/achromat, doublet SD/FCD100 and ED/??? ?

What is the glass in the ED or is it the same as SD?

There are 2 versions, apo and achromat, both doublet. Older apo version is triplet. No ed version.

Another fixed eps(yes, the zoom) version is not for public sale.


Edited by range88, 19 August 2022 - 01:44 AM.

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#21 wrighty338

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Posted 19 August 2022 - 03:20 AM

This one right?  smile.gif

The Kowa looks wonderful - maybe one day! Are there really only 3 eyepiece sets that fit? Which do you use MT4?




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