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BORG 107FL F3.9ED

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#1 Jon Rista

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Posted 21 November 2018 - 12:23 PM

I have been in the market for some new scopes for a while. I have been looking for both a fast newt, as well as a shorter refractor for wide field stuff. I was just pointed to the BORG 107FL F3.9ED scope, which appears to be a new design from Borg. The specs look quite impressive, for the given focal length. I am curious if anyone has actually used one or seen any images acquired with one? The overall package with this scope seems to be pretty much perfect...exactly what I was looking for. Almost too good to be true (heh, isn't that how it always is?)

 

Anyway, would love to hear what people think, and if there are any images out there taken with this scope, I'd love to know where.

 

Thanks!


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#2 jay.i

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Posted 21 November 2018 - 12:24 PM

Check this thread for some chatter about it. No one has bought it yet though.


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#3 einarin

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Posted 21 November 2018 - 12:30 PM

Just noticed this in one astro shop - so it's pretty recent addition and doubt if anyone yet is using it.

But very interesting scope.

AstroHutech owner Ted Ishikawa tells us, “As far as I know, this may be first optical design utilizing both fluorite and ED elements in same optical train.”

Only complaint about the price...



#4 TikiTom

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Posted 21 November 2018 - 12:30 PM

some Borg 107 photo results:

https://www.astrobin...4&camera_type=5

 

Hope to get one some time this winter. if they are available,

and true, Borgs are not cheap.... -LoL-....


Edited by TikiTom, 21 November 2018 - 12:35 PM.


#5 Jon Rista

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Posted 21 November 2018 - 12:36 PM

Check this thread for some chatter about it. No one has bought it yet though.

Thanks for the link.

 

The Borg is significantly cheaper than the FSQ106, especially when you throw a reducer into the mix (the Tak reducers are over a grand, so you could about get two of the Borg 107FL f/3.9 astrographs for the price of an f/3.somethingish FSQ106). It sounds like the standard design of the Borg is a doublet, but the astrograph version includes an ED group "in the focuser"...so I wonder how well corrected it is.


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#6 einarin

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Posted 21 November 2018 - 12:43 PM

Wasn't there an older model 107mm doublet @ f/5.6 ?

Maybe those astrobin images are taken with such (as they are taken last year).



#7 TikiTom

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Posted 21 November 2018 - 12:50 PM

Wasn't there an older model 107mm doublet @ f/5.6 ?

Maybe those astrobin images are taken with such (as they are taken last year).

Here some discussion about this 107 f5.6 from 2016:

https://www.cloudyni...doublet-coming/



#8 Jon Rista

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Posted 21 November 2018 - 12:54 PM

I don't know that the performance of an f/5.6 doublet would be all that great. From what I can see, the new 107FL f/3.9, when used in the fast astrograph configuration, has both Fluorite and ED elements, with the ED element being "in the focuser" (not sure if that is literally what they mean, or if it just means at the back of the scope). I would certainly hope that with both a Fluorite objective and ED corrector, the color correction would be better than a doublet.



#9 jay.i

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Posted 21 November 2018 - 12:55 PM

I doubt the 4-element reducer will correct the CA from the 107FL design. From Ted's LRGB/OSC photos it seems like there is still some bloat. If I wanted truly excellent correction at such a fast focal ratio, I'd go for the FSQ-106 with f/3 reducer. Somehow I doubt the Borg will even come close to touching it. Hopefully someone will take the plunge and let us know!



#10 AdamJ

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Posted 21 November 2018 - 04:41 PM

I have been in the market for some new scopes for a while. I have been looking for both a fast newt, as well as a shorter refractor for wide field stuff. I was just pointed to the BORG 107FL F3.9ED scope, which appears to be a new design from Borg. The specs look quite impressive, for the given focal length. I am curious if anyone has actually used one or seen any images acquired with one? The overall package with this scope seems to be pretty much perfect...exactly what I was looking for. Almost too good to be true (heh, isn't that how it always is?)

 

Anyway, would love to hear what people think, and if there are any images out there taken with this scope, I'd love to know where.

 

Thanks!

Its just my opinion but I have always thought that all of the Borg F4 scopes suffer from terrible CA.



#11 einarin

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Posted 22 November 2018 - 12:52 AM

These doesn't look too bad (although most them are NB):

https://www.astrobin...2/borg-101edf4/

https://www.astrobin...borg-125sd-f39/

https://www.astrobin...per-reducer-f4/



#12 medderx

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Posted 23 November 2018 - 06:47 AM

I doubt the 4-element reducer will correct the CA from the 107FL design. From Ted's LRGB/OSC photos it seems like there is still some bloat. If I wanted truly excellent correction at such a fast focal ratio, I'd go for the FSQ-106 with f/3 reducer. Somehow I doubt the Borg will even come close to touching it. Hopefully someone will take the plunge and let us know!

Yeah there is significant blue color around most stars let alone bright ones. Also if you pixel peek his is way out of collimation which makes me wonder about how much effort they are really putting into it. I don't see why any petzval especially one with FL and ED elements should have absolutely any color, the fsq does not have any from f/8-f/3 and it does not have a FL front element so what gives. It honestly seems like they are just trying to put a band aid over a bullet hole and calling it better than new.

 

I'm the guy that started the other thread, Ted was extremely helpful with figuring out possible custom backfocus but when I questioned the using the doublet design I was just thrown the fluorite card. Although I want to think the borg is perfect I'm now 100% sold on the fsq unless borg comes up with a new design for the front element/group and makes it a standalone astrograph rather than a crossover from a doublet. I think then it would have potential to be a tak killer.

 

Is a $4500 price tag asking for a stiff critique or am I being to hard on them for not having used the scope?


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#13 Fomalhaut

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Posted 23 November 2018 - 02:19 PM

 

Oh, very beautiful pictures, indeed!!!


Edited by Fomalhaut, 23 November 2018 - 02:41 PM.


#14 rockstarbill

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Posted 23 November 2018 - 07:52 PM

I doubt the 4-element reducer will correct the CA from the 107FL design. From Ted's LRGB/OSC photos it seems like there is still some bloat. If I wanted truly excellent correction at such a fast focal ratio, I'd go for the FSQ-106 with f/3 reducer. Somehow I doubt the Borg will even come close to touching it. Hopefully someone will take the plunge and let us know!

With all due respect, the F3 reducer for the FSQ106 is not of the best optical quality IMHO, nor is the Reducer QE built all that great (grub screws.... bad idea). The Reducer 645 is a great piece of equipment though, but costs $2500. Compound that with the Fisher Price quality focuser on the FSQ and it is really difficult to recommend that system to anyone that is imaging with something heavier than a DSLR camera. Collimation has also plagued that scope, and others that are of the same design. With a full focuser replacement and good collimation though, the FSQ is a champ. That is a lot to ask of someone to accept IMHO.

 

I personally sold my FSQ and TOA, and replaced them both with a AP 130GTX. Reduced with the Quad TCC its very close to the same FL of the native FSQ106 (585 vs 530), 24mm of additional aperture and a smidge faster at F4.5. With the field flattener, its F6.7 873mm, which works great as well. But.. of course that is an expensive option and I dont think Jon is looking to invest that much.

 

The term "wide" needs to be defined here though. There are other options, such as using the Quad TCC on a TEC140 (F5, 705mm) which would be 1.43° x 1.08° and 1.11"/px with the ASI1600 and 1.07° x 0.71° 0.7"/px with the ASI183MM. My guess is that Jon is looking for something more in the 400-500mm range. 


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#15 Jon Rista

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Posted 23 November 2018 - 08:46 PM

Definitely in the ~400mm range. I would go 300mm as well.



#16 rockstarbill

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Posted 24 November 2018 - 01:28 AM

First off, Go Huskies on a wonderful win.

 

In terms of the scope, WO is about to release a new short focal length Petzval based system. Its called the Redcat. 


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#17 Jon Rista

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Posted 24 November 2018 - 01:15 PM

I saw the WO Redcat. Tiny aperture of only 51mm, and it is f/4.9. There are not many scopes in the 300-400mm f/3-f/4 range. The reduced FSQ106 is one, the Borg is another. I came across a Vixen as well.

 

I am curious, what are the resell values of Borg scopes? Do they hold value well? If I get one of these 107mm f/3.9 scopes, and it turns out to not meet my expectations, I am wondering how well it might resell. If there is no resell value, then I will at the very least wait until someone has done some imaging with one to see how it fares.


Edited by Jon Rista, 24 November 2018 - 01:16 PM.


#18 rockstarbill

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Posted 24 November 2018 - 04:15 PM

I would imagine you could return it if it had issues. The Rosette frame posted from that scope does show some issues:

 

https://digiborg.wor...g-107fl-f3-9ed/

 

But who knows if the problem was the scope, camera, or the filter that was used. 



#19 orlyandico

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Posted 24 November 2018 - 10:59 PM

Borg really isn't in the same tier as Tak.

 

I was surprised at rockstarbill's opinion of the FSQ106, however - I had always thought that the '106 was the best flat field astrograph you could get. But turns out I was wrong. Seems an AP quad TCC is in my future...

 

That said, I found someone's STL11000 image from a '106 and it has perfect 9 micron round stars all the way to the corners. Which is something I have yet to achieve (although I have never imaged with my AP130 and don't have the quad TCC or the field flattener).


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#20 Jon Rista

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Posted 24 November 2018 - 11:22 PM

Yeah, not enough people use Borg scopes for imaging. Tough to find good example images. I've moved beyond the Borg...since its normal price is around $4500, and I am not sure the optical quality is really there. I am now looking at the VSD100 and FSQ106 again. Both seem to be really nice options...pricier, about six grand or so rather than forty five hundred, but they do have the optical quality, and both have huge image circles, so a very well corrected field even for larger sensors. And both are (or can be) quite fast, which is what I need.


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#21 orlyandico

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Posted 24 November 2018 - 11:40 PM

Jon, if you only want to illuminate a full-frame sensor, why not get the ubiquitous 80mm f6 triplet and add the 395 EUR Riccardi reducer?

 

https://www.apm-tele...075-x-m63-small

 

https://www.apm-tele...75x reducer.pdf

 

The spot diagram (second link) shows 12 micron stars at 21mm off-axis which is the corner of a 35x24mm full-frame sensor. Not quite as great as a '106 but not too bad either. So for under $1000 you've got (9/12) = 75% of an FSQ106! come to think of it, I do have an 80mm f6 Lomo.. maybe I should buy that Riccardi and stop using my Televue 0.8X FR/FF.

 

There's a discussion of flatteners for the fabled Lomo 80mm here - http://www.astrocafe....php?f=21&t=724

They concluded that the TSFlat2 and Borg 7887 were the best matches for the 80mm f6 on full-frame. Surprisingly the Skywatcher 0.85 does better than the Televue 0.8X. I'd be happy with those corner stars..

 

The AP quad TCC is $1520. I think I'll settle for the $825 field flattener and live with the slightly longer focal length..



#22 medderx

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Posted 25 November 2018 - 12:30 AM

With all due respect, the F3 reducer for the FSQ106 is not of the best optical quality IMHO, nor is the Reducer QE built all that great (grub screws.... bad idea). The Reducer 645 is a great piece of equipment though, but costs $2500. Compound that with the Fisher Price quality focuser on the FSQ and it is really difficult to recommend that system to anyone that is imaging with something heavier than a DSLR camera. Collimation has also plagued that scope, and others that are of the same design. With a full focuser replacement and good collimation though, the FSQ is a champ. That is a lot to ask of someone to accept IMHO.

 

I personally sold my FSQ and TOA, and replaced them both with a AP 130GTX. Reduced with the Quad TCC its very close to the same FL of the native FSQ106 (585 vs 530), 24mm of additional aperture and a smidge faster at F4.5. With the field flattener, its F6.7 873mm, which works great as well. But.. of course that is an expensive option and I dont think Jon is looking to invest that much.

 

The term "wide" needs to be defined here though. There are other options, such as using the Quad TCC on a TEC140 (F5, 705mm) which would be 1.43° x 1.08° and 1.11"/px with the ASI1600 and 1.07° x 0.71° 0.7"/px with the ASI183MM. My guess is that Jon is looking for something more in the 400-500mm range. 

So I've heard from others that tak focusers are not the best but how bad are they really? Is it just that you should be getting one of FT quality for the price the scope is or do you think they are really as bad a Chinese crayford focusers? Same with the QE reducer, as that's the first time I've heard a major complaint about it. 



#23 orlyandico

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Posted 08 December 2018 - 10:22 PM

On the low rent scale.. William-Optics has a new adjustable flattener that supposedly will work with any focal length and covers 97% of full frame.

 

I did some least-squares fitting in Excel to figure out the correct distance for this new flattener for "any" refractor you may have. My copy of the flattener has arrived but I have yet to test it as am traveling.

 

https://orlygoingthi...-flattener.html

 

It is 1/3 the cost of the AP flattener so worth a gamble I guess..  and in any case the TV 0.8X is one of the worst performers with the Lomo 80mm f/6 so even if the WO flattener is a bust on my AP130 I can still use it on the Lomo.


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#24 Spikey131

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Posted 08 December 2018 - 11:26 PM

Just curious.  Why isn't the Televue NP101is in this conversation?


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#25 medderx

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Posted 09 December 2018 - 12:42 AM

Just curious.  Why isn't the Televue NP101is in this conversation?

Well the borg is a smidge over a full stop faster than the 101is, the whole point of it is to be fast. 

 

But the televue is nice, I considered it back when I was looking for my first astrograph.


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