107 replies to this topic

[salico]

Maybe it's just your style to over-exaggerate your reactions and responses.

Increase the content versus discussion ratio and we might get used to that.

Check my reactions to ANY other person on the whole forum than this certain one. Here I defended the honour of a wonderful telescope maker, Mr Schumann, who even isn't save from false statements after having  passed away...

Edited by salico, 13 April 2020 - 04:30 PM.

[Pinac]

Hi salico,

I think you don‘t have to defend the honour of Mr. Schumann - those of us who are familiar with the name Binoptic know that his telescopes were/are the best (yes, the likes of Oberwerk and APM are getting closer in optical and mechanical quality, but they still have some way to go, according to my own experience), and the younger ones who do not know Binoptic will not be impressed, whatever you say.

I once was almost ready to order a Binoptic, but missed the opportunity, and then it was too late. So enjoy yours as much as you can!

 

Pinac

Edited by Pinac, 14 April 2020 - 03:46 AM.

[range88]

The Borg fluorite doublets may not be as good as you think if you expect an APO-like experience.

All in all they are just fast doublet, but they excel at low power for their 2'' eyepiece compatibility.

If you want excellent planet performance in a binocular setting, make sure you go down another(heavier and more expensive) route.

[range88]

It is a little bit off topic, neither APM nor Borg, but your Binoptic binos sound very interesting. I was aware that Binoptic offered the bigger binos (> 150, 175mm) with 2", but you have a 120 mm ED, the one with the nice center mount? Could you please post pictures, you seem to have very rare, interesing instruments.

 

best regards and many thanks

 

Thomas
 

The biggest binoptic binoculars is in Shenzhen, China, a 304mm giant.

It has a long long neck between the 2 reflecting mirrors. To be honest, I much more prefer EMS than 3-mirror.

The only advantage of a 3M system I can think of is it's so swap friendly. 

[range88]

I ve watched stars moving to the edge of the field, not losing brightness. Will try with a defocussed one next time.

Use the Masuyama 32mm, and you will see what is losing brightness.

The PO27 and N22 only have 30mm or so field stop and will not clip in your setting.

[salico]

wont do anymore. Had enough of it. Nobody can convince me, that 3M are bad, they are excellent. Would never use the Masumoto System though...

Edited by salico, 14 April 2020 - 11:35 AM.

[ratnamaravind]

There certainly seem to be part to part variations- I ended up with a good 90FL.

 

The Borg fluorite doublets may not be as good as you think if you expect an APO-like experience.

All in all they are just fast doublet, but they excel at low power for their 2'' eyepiece compatibility.

If you want excellent planet performance in a binocular setting, make sure you go down another(heavier and more expensive) route.

[Pinac]

The Borg fluorite doublets may not be as good as you think if you expect an APO-like experience.

.....

.....

I have seen the single tube Borg fluorite. Based on that, I am pretty sure the doube-tube version will be good enough for me 

[range88]

I have seen the single tube Borg fluorite. Based on that, I am pretty sure the doube-tube version will be good enough for me

I've seen borg 55 90 107, they are consistently good.
But don't make me wrong, they are just not as good as my Lzos 123 at high magnification. One glimpse difference.

[Pinac]

I've seen borg 55 90 107, ......
....... ....... they are just not as good as my Lzos 123 .....

As I said: they will be good enough for me 

But I am glad that you got the even better equipment - I wouldn‘t have expected anything else ...

[ArsMachina]

The Borgs often do have relatively short focal length.

Shorter focal length can not provide the same optical performance as a longer focal length (but does provide wieder fields, what is their intension)

Borg is using doublets (not sure for the fl ones, I am not common to them) what can not provide the same optical performance as a triplet like the Lzos...

But a doublet does has a weight and cooling advantage.

 

So it always depends on your needs...

Wide fields, low weight : Borg

Perfekt performance for planetary use: longer focal length Triplet APO

 

Jochen

Edited by ArsMachina, 15 April 2020 - 07:33 AM.

[Pinac]

Borg 90 APO Fluorite Binoscope 500mm f/5.6, binocular version as configured by AOK Lucerne, mounted on Vixen fork mount, with 7mm  DeLite eyepieces.

 

Looking forward to testing it - when I get time, and once the weather permits.

 

Pinac

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Edited by Pinac, 13 May 2020 - 12:31 PM.

[alpha_centauri]

Hi Pinac,

 

Thanks for the update! The binoscope looks cool. Looking forward to your review!

 

Elan

[Pinac]

BORG 90FL Binoscope - Initial impressions

 

For me, the Borg 90FL BT (Binocular Telescope, Binoscope) has been a revelation in a number of ways.

 

I have been using BTs for years, all of them angled at 45 degrees (Vixen, APM, Oberwerk, Kowa, see signature field), and I have also been using large straight-through binoculars (Docter Aspectem, APM 28x110). I have used 90 degree angled instruments (for instance,  my Celestron 6” SCT with the Zeiss binoviewer superbly tuned by Denis) but never really became a fan of the 90 degree setup, 45 degrees always seemed to me the optimum configuration.
So when I ordered the Borg 90FL, it was a step into the uncertain: would I become comfortable with the 90 degree angle?

 

Moreover, the Borg BT, which is  essentially just two separate tubes mounted on a special platform (instead of the more integrated format of the other BTs), features an image erection system (EMS = Erecting Mirror System) from Matsumoto instead of prisms. The internet is full of contradictory statements about how easy or tricky it is to align the tubes and find perfect collimation with such a system.

 

Finally, having only briefly experienced the optical quality of a single tube Borg 90FL, I had some concerns that a highly modular double tube instrument such as the Borg might neither be very easy to mount nor easy to handle.

 

The notes hereafter about my initial impressions of the BORG 90FL BT and the experiences made when using it reflect my own learnings along the way.
____________

 

Borg of Japan produces a line of astronomical telescopes, components and accessories for the hobby astro markets. A special characteristic is the high modularity of Borg’s product lines; this allows for a large number of combinations and the possibility of combining many Borg components with third party elements.

 

Astroshops like e.g. AOK of Lucerne, Switzerland,
http://www.aokswiss.ch/index_bino.html
use this modularity to offer a wide range of configurations for single or double tube Borg telescopes and mounts.

 

The instrument presented here has at its core Borg’s 90mm tube with the f/5.6 Canon Optron fluorite doublet objective (the same as in the former Takahashi Sky-90). In accordance with my order, AOK combined two of these Borg tubes and mounted them on a purpose-built “BB-140” platform, see
http://www.aokswiss....oer/bb-140.html
to create a binocular telescope, each tube fitted with a Kasai dual-speed focuser (similar to the famous “Feathertouch” type) and a medium-size Matsumoto EMS (“Erecting Mirror System”).

 

I chose a configuration with 1.25” rather than 2” eyepieces, because I have already a large selection of eyepieces in that size; plus, one of the main benefits of 2” eyepieces is the possibility to get very wide field views, esp. at low magnifications, something that is of a lesser interest to me (I tend to use binoscopes mainly with medium or even high magnifications, whereas I mainly use large “regular” binoculars for sweeping the night sky).

 

 

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[Pinac]

(cont'd 2)

 

I found the instrument assembled and supplied by AOK (I call it “the Borg” hereafter) to look a bit “technical”, almost a little “DIY”, and definitely less elegant than e.g. an Oberwerk 100XL or an APM 70 ED. But I quickly forgot about that once I mounted the Borg on the Vixen fork mount, for which AOK had slightly modified the mounting plate. Two positive findings: First, the BB-140 platform sits at the center of gravity; none of my other BTs (Vixen, Kowa, APM, Oberwerk) is as perfectly balanced, which makes mounting the Borg on tripod very easy (the same is true for carrying it on the red handle). Second, AOK has structured the underside of the BB-140 platform on which the two tubes are fixed in such a way that I don’t have to look for the exact location on the mounting plate of the fork mount, the platform almost “snaps in place” on the mounting plate and lets me screw it on without having to hold it; this makes mounting and removing at night very easy, much easier than what I was used to so far.

 

For binocular instruments built with two separate tubes, it is critical to mount the two tubes in a way that allows changing the interpupillary distance (IPD) without losing the parallel orientation of the tubes. To adjust IPD, you can either adjust the optical elements, or you can change the horizontal distance between the tubes; for the Borg, it means moving the entire tubes on their platform further apart or closer together. The challenge with that is to keep the orientation of the tubes absolutely parallel in the process. AOK has chosen to use what they call “high precision ball cage linear bearings” specially made by Agathon, a Swiss mechanical engineering company. The BB-140 platform used for the reviewed instrument lets you simply push (by hand) the right tube towards or away from the left one; the right tube glides on two of the mentioned special bearings, and as far as I could experience, the parallel orientation of the tubes is extremely well maintained in the process (the arrow in the pic shows one of the two bearings).

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Edited by Pinac, 02 June 2020 - 12:20 AM.

[Pinac]

(cont'd 3)

 

For those not familiar with the Matsumoto type “EMS”: these work with mirrors instead of prisms and produce an upright, true-sided image like a binocular. Their specific advantage: once the two tubes have been roughly aligned on the binoscope’s platform, the fine-tuning of the alignment can then be effected directly during the observation using two little knobs, one for up-down and one for left-right, situated on the outside of the right-hand EMS unit. I was a bit worried that this might not work as easily “as advertised”, but it does! In my brief experience, the Borg provides a much more satisfactory alignment situation than the “experimenting” I usually perform on the helical eyepiece holders of my APM, Vixen or Oberwerk BTs. In my current BTs, I sometimes have to take the eyepieces out again, re-insert them and try to find the right amount of fixation of the eyepiece in its holder by tightening and loosening it and rotating the eyepiece, until the double image is completely gone (the Vixen BTs don’t actually allow that procedure, you can only insert and remove eyepieces, there is no mechanism to tighten the holder. The same is true for the Highlander, but the latter provides a very tight fit for its eyepieces). The alignment fine-tuning is both easier, faster and more precise with the EMS on the Borg. The eyepiece holders of the Borg also provide a more effective and tighter fit of the eyepieces than APM or Oberwerk do. Overall, and this is particularly relevant at higher magnifications, alignment is both easier to achieve and allows more comfortable viewing at high magnifications in the Borg than with my other BTs.

 

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[Pinac]

(cont'd 4)

 

Observing with a binoscope that has fitted EMS means observing at a 90 degree angle. There have been debates here on CN whether 45 or 90 degree is the best configuration, and I am not going to get into that again. I used to be supporter of the 45 degree solution, finding it the best compromise among the three possible solutions (0, 45, 90), but after having used the Borg for a short while now, and despite my initial concerns, I start to see the advantages of the 90 degree configuration. For targets not too high over the horizon (e.g. Venus), working with the 90 degree angle is perhaps slightly less intuitive than with a 45 degree instrument, but I think the main handling difference is the “transition” from locating a target in the red dot finder (looking forward) and observing through the eyepieces (looking downward). That “transition” appears a bit less natural with a 90 degree than with a 45 degree angle. Thereafter observing the target at a 90 degree angle can be as comfortable as at a 45 degree, depending on what position you take behind the instrument (I often sit on a chair with adjustable height).
With targets at higher elevation, say 60 degrees and more (e.g. the current moon), the 90 degree angle has clear advantages over all other designs and I found it makes observing much more comfortable.

 

I was a bit worried about the weight of the Borg; I am not a strong person, and mounting instruments heavier than, say, 12-14 pounds, esp. at night, is not my type of activity. The Borg weighs just under 6 kg (13 pounds) w/o eyepieces, just a tad more than the Oberwerk 100 XL and about half a pound less than the Kowa Highlander. Due to the special shape of the purpose-built platform, mounting on tripod and de-mounting is actually easier and requires less effort than expected.

 

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[Pinac]

(cont'd 5)

 

I started my first observation during daytime, using 10mm Vixen SSW eyepieces (50x).
Immediate irritation: AOK had supposedly aligned the two tubes before I got them, and I had anticipated that I had to just fine-tune alignment using the two knobs on the EMS, but there was not enough left-right / up-down travel on those. So I had to first roughly re-align the tubes again. This turned out to be much easier than expected. The manual downloaded from AOK’s website indicated 4 screws on the side of and below the mounting platform, two of which work in “push” and two in “pull” function, allowing alignment of the tubes horizontally and vertically. It took me about 5 minutes to perform the entire procedure, including searching for the right size screwdrivers (I remembered only later that AOH had actually provided me all the necessary tools, which I had already stored), and I did not even have to dismount the Borg from the tripod.

 

Then  back to observing. I chose a street sign 1.2miles away to focus for both eyes, then fine-tuned the alignment with the two knobs on the right-hand EMS, first vertically, then horizontally, as recommended by AOK. Checking the result by taking my eyes off the eyepieces, waiting for a few seconds, then looking through the eyepieces again – perfectly aligned! Sharp and bright image, as hoped for.

 

Later that evening, first light on a partly cloudy sky observing Venus at 9:30 pm, using 7mm DeLite eps (71x). Conditions were not great, but I got an outstandingly clear and crisp image of crescent Venus in the Borg. For comparison, I put the Borg side-by-side with the Oberwerk 100XL ED (9mm Nagler eps, 62x). Venus stood already relatively low, and the air turbulence impacted the image quite a bit, more so in the Oberwerk than in the Borg, which I found surprising, I would have guessed the opposite, due to the higher magnification of the Borg. The Oberwerk showed just slightly more color than the Borg (which didn’t show any), not too bad, but noticeable. Also, due to Venus’ brightness, there was a tiny bit of a “halo” around the planet’s image in the Oberwerk, which was totally absent in the Borg.

 

On May 20 at 9:20 pm, the sky was clear, and this time, I compared the Borg side-by-side with the Kowa Highlander. I used 9mm Kowa eyepieces, of which for some odd reason I happen to have two pairs, in both instruments (note: while you can only use Kowa’s own eyepieces in the Highlander, the Borg, like many other binoscopes - e.g. Vixen or APM – works well with Kowa eyepieces). The 9mm Kowa eps give 50x magnification in the Highlander and 55x in the Borg. I found the image very comparable in both instruments, nice sharp image with no color fringes in either; the Borg with its larger aperture was a bit brighter, despite the slightly higher magnification.

 

Learning from that evening: after a change of eyepieces, you may have to fine-tune the conditional alignment on the Borg. Since this is effected by using the two knobs placed at the right-hand EMS, it takes 5 seconds and is no issue at all (concerns in some  threads that this might be complicated and / or time consuming are totally unfounded), it is actually easier and provides better results than the adjustments I have to perform on the eps holders of my APMs or Obies  after changing eyepieces).

 

May 24 afternoon: daytime observation of various targets, comparing the Borg (Nagler 9mm, 55x) with the Swaro BTX (60x95). The image in the Borg was clearly brighter – no surprise -, sharpness** better in the Borg, contrast** however about the same, which shows that brightness alone is not “always everything”.
** I am using the terms sharpness and contrast here “literally”:
Sharpness = how small is the transition area between light and dark in the image
Contrast = how strong is the difference between light and dark sections in the image

 

May 26 early evening: observing the 4 day old crescent moon with the Borg (9mm Nagler, 55x), the Kowa Highlander (9mm, 50x) and Oberwerk 100 (9mm Kowa, 62x). No color fringes in the Borg and the Highlander, very little in the Oberwerk. Detail recognition is best in the Borg, second Highlander, last Oberwerk (the latter also exhibited difficulties in achieving a fully aligned image, I had to re-insert and rotate the eps several times and I also switched with the eyepieces from the Borg until I got satisfactory alignment of the images in the two tubes. My sample of the 100XL Obie is unfortunately more prone to double images than my 82XL).

 

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[Pinac]

(end of post)

 

May 30, 2020, 10:30 pm: The crescent moon is now 8 days old, and seeing conditions are very satisfactory. I observe with 7mm DeLite (71x) and 5mm DeLite (100x) eyepieces in the Borg. Stunning detail on Theophilus, the central mountain easily split in its 4 segments; just north of Theophilus is Sinus Asperitatis, the unnamed plateau-like structure within it is again well visible; easier targets like Rupes Recta or Vallis Alpes appear crisp and clear; crater Hyginus with its double 110km valley structures called Rima Hyginus are nice and distinct and easy to locate, I do not remember having seen them that clear in a binoscope.

 

I have not myself performed a star test yet. Roger Vine on “Scope Views” has done one on the single tube  of the Borg 90FL and writes: “… The star test is good, probably better than ¼ PV”.
He further writes that “… the objective has some of the best coatings I have seen…” He finds “false colour … well suppressed for such a fast doublet” and rates the 90FL objective overall as “outstanding”. See his full review of the Borg 90FL tube under
http://scopeviews.co.uk/Borg90FL.htm.

 

One thing I prefer in other BTs like the Oberwerks, APMs or the Kowa Highlander:  they are all to a large degree at least splash- and dustproof. The Borg isn’t, at least not in the configuration with a Feathertouch - type focusing unit like the one from Kasai on this instrument, which has parts that move into and out of the back of the tube (maybe with a helical focuser, things would be a bit different?). So I guess I have to be a bit more careful with the Borg in humid and / or dusty environments (?).

 

The Borg as presented here is much more expensive than any of the similarly sized APMs, Oberwerks or Vixens that I know, and still more expensive than the Kowa Highlander. Is it worth the price difference?
Everyone will have to decide that for him- or herself. I was looking for something that would give me a better optical performance than my current BTs, yet would neither be heavier nor larger. I had once planned to acquire a Binoptic BT but missed the moment before that company disappeared. With the Borg, I have the impression that I might have found something (almost) as good in terms of optics and versatility as a Binoptic.

 

If I were to rate the Borg based on my experience so far, using a “Pluses / Minuses” system, I would say the following (true for this configuration by AOK of the Borg 90FL binoscope):

 

+ Relatively light-weight and compact for a 90mm binoscope,
+ Very easy and effortless to mount
+ Conditional alignment is easy, fast and extremely effective
+ FL lenses provide sharp, almost color-free and high-contrast images even at high magnifications
+ double-speed focusers allow fast and precise focusing
+ all standard eyepieces will come to focus
- system not sealed, neither dust- nor splash-proof
- no accessories (including case) unless you buy separately

Based on the good experience with the Borg so far – the Borg clearly outperforms my other BTs in terms of image quality - I am looking forward to the summer months when the large planets become nighttime targets. Until now, the Borg has exceeded my expectations; I am particularly fond of the superb brightness and contrast of the image and the excellent alignment that I can achieve without any trouble, making high magnification viewing a pleasure. And since it seems to have plenty of further “magnification potential” beyond the 100x achieved with the 5mm eyepieces, I am considering to acquire 3mm (possibly 3.5mm) eyepieces to be able to go higher in magnification.

 

fwiw
Pinac

Edited by Pinac, 01 June 2020 - 09:29 AM.

[bcarter1234]

Pinac,

 

Thanks for the excellent review. I'm sure you are going to have a wonderful summer. You need to get Williams Optics to loan you one of their 103mm binocular telescopes so you can do a side by side review. ;-)

 

Would you consider a pair of Barlows for higher power views? Now that you have quick and easy conditional alignment literally at your fingertips you no longer have to be concerned with merging. The views through two GSO 1.25" 2.5x Apochromatic Barlow Lens # BL251 in Mr Bill's Bino Box Redux have been very satisfying. Most people say they are actually closer to 2.2X.

 

If you want to try something for fun see if you can find two eyepieces that differ in focal length by about 15% and will come to focus at the same height. For example a 23 and a 20mm. They provide a wonderful 3D effect in the center of the field. I had a great time looking at M42 with such a pair.

 

Please keep us updated.

 

Take care,

Brent

[Rich V.]

Excellent report as we have come to expect from you, Pinac.  Very clear and thorough with your detailed photos.  Thanks for the great read!   

 

Rich

[KennyJ]

Thanks for that great, comprehensive and well illustrated review, Pinac.

 

Kenny

[oldmanrick]

Pinac,

 

Thanks for the well-written, comprehensive report.  For me, very interesting and informative reading.  You appear to have a very fine and enjoyable instrument that will provide much satisfying use in the future.  Congrat's, and looking forward to more of your awesome reports!

 

Rick

[alpha_centauri]

Hello Pinac,

 

Thank you very much for the comprehensive and helpful initial impressions!  The scope looks beautiful and it is great that the tuning is so convenient and easy. Looking forward to your summer night impressions of the scope. Must be exciting to play with various different configurations like Brent said, now that you have all three degrees of freedom to shift the optical axes. And to take one tube along as a travelscope or a spotting scope (in not so dusty environments). Thank you and wish you a lot more fun with the binoscope!
 

Elan

[Pinac]

.....

.....

.....  You need to get Williams Optics to loan you one of their 103mm binocular telescopes so you can do a side by side review. ;-)

 

Would you consider a pair of Barlows for higher power views? ......

.....

.....

.....

Thanks, Brent. Yes, the William BT seems very interesting, I wonder how good it is (is it a true apochromat?), and the version in the colours white and gold looks incredibly nice.

 

I have used Barlows many years back, but not for a long time now; this is actually a good idea that I may pursue. Thank you for the tip!

 

Pinac