71 replies to this topic

[Ken J Cunningham]

Ok, so I’m a new Borg owner and noticed that there is no “itis” style thread for Borgs like there are for Taks, APs, etc. so, since I’ve taken delivery of a lovely new Borg 90fl, I thought I’d start one as a place to geek out with others over all things Borg.

 

What brought me to owning this new Borg you may ask? I had been circling around the idea of putting together a travel scope setup for a bit. On the list were Tak 60q, Tak 76dcu, TV 85, Borg 71fl, and Borg 90fl.
 
The idea was for this scope to be light and portable for travel, packable into a photo backpack along with a light weight mount, as well as being used at home as a wide field complement to my Tak FC100dl and C8.
 
After some back and forth with other members of the board, I decided to go for the Borg 90fl OTA with 2 inch Kasai R&P Focuser. For me, it ticked all the boxes, giving me a very small scope relative to the other choices on the list, without sacrificing much in the way of aperture.

 

This Monday my Borg 90fl arrived. I was greeted by a lovely box of Borg parts. This seems to be part of the appeal of these Borg scopes. They are like little puzzles that allow you to set the scope up in different ways.

 

 

Once assembled, what I had in my hands was a small and lovely 90mm scope that comes in at length of 16 inch with no diagonal and the dew shield retracted.

 

 

Here it is on my Stellarvue M2c mount decked out with the More Blue rings. It balances on the mount nicely, even with the Ethos 17mm.

 

Of course with the arrival of the new scope, Monday night was quite cloudy, so I didn’t get to do any real observing, but there were enough gaps that I was able to test focus on all my eyepieces and they all came to focus so hooray!

 

For the limited amount of time I got looking thru the scope, I can already tell I’m going to enjoy using it immensely. The fit and finish on the scope is lovely. The Kaise r & p focuser is solid and smooth. The wide field views are lovely from what I was be able to tell thru the gaps in the clouds. It will be a nice compliment to the rest of my scopes which are mostly f9s and 10s.

 

Looking like I might get some clear skies later this week so will report back with more once I’ve had a chance to do a solid observing session with the scope.

[desertlens]

Enjoy the new scope. I grew very fond of the 90FL very quickly. I too discovered some difference between the parts sequence required and the photos I had seen. But it only goes together one way, which is helpful.

 

 

 

[Anthony236J]

Nice Borg 90FLs! I seriously considered one but just couldn't go ahead with it in the end. But I do have a 55FL that I use often and really enjoy.

 

 

I've been successfully resisting the 72FL (and originally the 71FL) for years now... but it's been a struggle.

[Dave Novoselsky]

Welcome to the Borg Collective.

[Ken J Cunningham]

Nice Borg 90FLs! I seriously considered one but just couldn't go ahead with it in the end. But I do have a 55FL that I use often and really enjoy.

 

 

 

I've been successfully resisting the 72FL (and originally the 71FL) for years now... but it's been a struggle.

Those 55fl’s look nice. Have been finding myself looking at the 55fl’s different configurations on Hutech’s site and watching Buyee for used Borg parts. Resistance is futile indeed!

[Dave Novoselsky]

Those 55fl’s look nice. Have been finding myself looking at the 55fl’s different configurations on Hutech’s site and watching Buyee for used Borg parts. Resistance is futile indeed!

Of course there is another 55 mm fluorite in current production, the Vixen FL55SS, the  last fluorite scope in their line.

 

Pretty much the same size as the Borg but at f/4.3 as opposed to the Borg at f/5.6 more a pure astrograph where the Borg, depending on addition or removal of an included tube section, can double as visual and astrograph. The Vixen is also a TAD more expensive, priced at  $1148.98.  

Edited by Dave Novoselsky, 07 April 2024 - 01:35 PM.

[Lentini]

Just paid for another Borg 50mm… I’m very excited! 
 

The one I have now is used as a dream RACI finderscope. The new one comes with tube rings, which might make it easy to use as an uber-lightweight grab-n-go. Might have to be dual-use.

 

No pics is boring, so here is my current Borg 50mm.

Attached Thumbnails

• 

[rainycityastro]

I’ve had a Borg 71FL for about 10 years. It is the perfect travel scope.

[desertlens]

I look forward to sweeping the southern Milky Way with this one.

 

 

A 72FL which shares a focuser/tube/case with a 90FL objective. The ability to swap objectives is a treat.

[desertlens]

This was my very first Borg instrument, a 55FL set up for visual use. I'd been doing some experiments with a 60mm finder and was impressed enough to invest in some small fluorite optics. I never imagined viewing the Veil nebula (all of it) with an OIII filter and a 25mm Ortho at this aperture. It just defied all logic.

 

Edited by desertlens, 15 April 2024 - 01:18 AM.

[Lentini]

What location and conditions were you viewing the Veil from? I assume you were in a really dark site?

[Scott99]

What is the f-ratio of the 90FL?   I'm interested in how the lens compares to the perfection of the 100DL.  I've always been interested in one of these uber-lightweight Borg scopes. 

[Ken J Cunningham]

What is the f-ratio of the 90FL? I'm interested in how the lens compares to the perfection of the 100DL. I've always been interested in one of these uber-lightweight Borg scopes.

You can get various configures. The one I got (ota with kasia r&p focuser) runs at 5.6. You can get so astrophotography setups running at f4 and f3.6.

I find it to be a complement to Tak 100dl. It renders a much wider field.

Quality wise, I find it compares favourably.

So far I’ve seen no CA even looking at Jupiter and the Moon.

It does have more field curvature and some softening at the edge of the field but with my Ethos I have to really crank my eye to the edge to even see it and as I move down towards 8 and 6mm it’s starting to go away. Either way not a problem.

My DL renders a darker field, but that’s to be expected givens it an f9.

Sharpness is equivalent.

[Mark9473]

My DL renders a darker field, but that’s to be expected givens it an f9.

Could you make that comparison at the same exit pupil size?

[desertlens]

What location and conditions were you viewing the Veil from? I assume you were in a really dark site?

Yes, I'm at 8K feet altitude which works for good transparency and I usually get SQM-L readings of 21.5 MPSAS or better. Seeing however is seldom better than 3/5 due to mountainous terrain which causes a lot of instability in the air.

Edited by desertlens, 15 April 2024 - 12:46 PM.

[Scott99]

You can get various configures. The one I got (ota with kasia r&p focuser) runs at 5.6. You can get so astrophotography setups running at f4 and f3.6.

I find it to be a complement to Tak 100dl. It renders a much wider field.
 

Sounds great, if it's even in the same ballpark as the DL at f/5.6 it's doing well!   It's tiny in comparison to the DL.  Most of my eyepieces work better at f/8-f/9 but I've always kept my Pentax XW 30mm for shorter-focus scopes, it worked well in the last f/5.6 refractor I had.
 

[Ken J Cunningham]

Could you make that comparison at the same exit pupil size?

The closet matching exit pupils I have between the scopes would be the 8mm Ethos on the Borg and the 13mm Ethos on the Tak. That would be 1.42 compared to 1.44. I’ll do a comparison some time this week and get back to you.

[Dave Novoselsky]

How how about this for the truly Borg obsessed looking for a replacement for the now unavailable but much missed mini Borg refractors:

 

“BORG 36ED EAA Set – 3964

Ideal configuration for EAA(electrically-assisted astronomy) application

36mm ED F5.6/200mm 270g / 240mm
Includes 2037, 5 various extension tubes, Arca Swiss mounting base, non-rotating helical focuser(7315) & Vixen-compatible plate (3125)
Quite lightweight system package
Allows for the visual use with a 1.25″ diagonal by removing some of extension tubes”

 

270 g is basically nothing at all! I have used the larger version, which works just fine is a visual instrument by as stated above removing a single tube segment or as I did, not installing it in the first place.

 

So why use a 36 mmED refractor? Besides being a great guide scope its tiny dimensions lend new meaning to the phrase “grab and go.”  Plus, it’s just a giggle under any circumstances.

Edited by Dave Novoselsky, 16 April 2024 - 01:32 PM.

[jay.i]

I bought a Borg 90FL several years ago, with the helical focuser, hoping I could keep the OTA slim, not wanting to shell out even more for a nicer focuser. I was stunned by significant field curvature with my 21Ethos and had issues obtaining sharp focus with the helical focuser. I ultimately returned it to Ken at Hutech who was gracious enough to accept the return. I was sad, because the size and weight of the OTA made it such an epic portable premium scope, especially given the fluorite optics.

 

Fast forward a couple years later and I managed to get my hands on a 90FL objective for a very good price. I now had a FeatherTouch focuser in my possession and I was willing to give it another go. I purchased the tubes and adapters I needed, already having rings and a dovetail, and slapped the FeatherTouch on it when it all arrived. Boy, was that the ticket. I don't know if the first objective I got had issues, or if the 21Ethos and helical focuser just made it seem like there were more issues than there really were, but... this 90FL is the deal! I used it several times with a NV intensifier, mostly afocal with the TeleVue 67Plossl, and later combining that with a 0.75x reducer, and 3/5nm Ha filters, easily bagging objects like the Horse Head and North American Nebula from my home Bortle 7 skies on an average night. With its relatively fast native focal ratio, it makes an excellent NV host.

 

Due to a variety of life circumstances, I haven't observed more than a handful of times in the past 3 years, much to my sadness. I longed for the experience, that wow factor, once again. Finally, just the other night, I got the itch, and took my 90FL out in the driveway to look at the waxing moon, on a night surprisingly clear, and popped in a 6Ethos. Boy I almost forgot what it felt like to look through some razor sharp high contrast optics! I asked my girlfriend if she wanted to come out and take a look, like when we started dating, and she obliged. She remarked how incredible the moon looked, how sharp the edges of craters were, how inky the shadowed craters were. And that was only at 83x! The seeing looked pretty good actually, possibly begging for more magnification, but I was happy to just soak up this moment, not trying to push it. As a casual instrument, while expensive, I think the 90FL hits a sweet spot of size to performance ratio.

Attached Thumbnails

• 

[Dave Novoselsky]

The “standard“ set for the 90 FL now includes a Kasai R&P two speed focuser which is actually very nice. A FeatherTouch is offered as an option, obviously for a higher price. My 90 uses the Kasai but several of my other Borg use the helical. Focus with those has been very sharp and precise, recognizing that to obtain the best focus the drawtube and the focuser must be manipulated in conjunction.

 

I have not had the same problem you encountered with similar but not identical eyepieces with the current Borg helical focusers. Seems to be an interaction between this particular scope and this particular eyepiece.

Edited by Dave Novoselsky, 17 April 2024 - 12:01 AM.

[desertlens]

I'll second Dave's comment regarding the Kasai focusers. I'm using the Kasai Crayford which was available for the Borg Series 80 tubes prior to the introduction of the R&P. In terms of smooth motion and load lifting capacity, it's every bit as good as the Baader Diamond Steeltrack which I use elsewhere. Both Kasais have FT properties at lower cost.

Edited by desertlens, 17 April 2024 - 01:35 AM.

[jay.i]

The “standard“ set for the 90 FL now includes a Kasai R&P two speed focuser which is actually very nice. A FeatherTouch is offered as an option, obviously for a higher price. My 90 uses the Kasai but several of my other Borg use the helical. Focus with those has been very sharp and precise, recognizing that to obtain the best focus the drawtube and the focuser must be manipulated in conjunction.

 

I have not had the same problem you encountered with similar but not identical eyepieces with the current Borg helical focusers. Seems to be an interaction between this particular scope and this particular eyepiece.

The 21Ethos is pretty heavy, as was the 2" Baader BBHS diagonal, and I think it was too much weight on the drawtube. I had it outside in winter and actually broke the glue attaching the grippy part to the helical mechanism itself, which reattached fine when it got warm. However when I sent everything back to Ted, I didn't get a refund on the focuser because he said it was unusable, or something to that effect, so... I'm not really sure what the deal was, as I didn't deliberately pull down or push in any direction I shouldn't have. I did even try to guide the diagonal in and out when focusing in and out. All I know is it wasn't up to the weight I had on it. If I had only used a 1.25" diagonal and 1.25" eyepieces, it probably wouldn't have been an issue. I did consider the Borg R&P focuser at the time but tried to keep it cheap as I mentioned; it seems the Kasai ones are even nicer now and they look pretty sharp too!

[skyops]

*

 

I found the r&p worked fine, but but the American FT was better. Just a matter of how much you wanted to spend, that's all. 

 

 

 

 

 

 

. 

[Scott99]

How do you find out how much these cost?  I can't find it anywhere online.  For the basic 90FL with the R&P focuser?

[desertlens]

Scott99, Check here:

https://astrohutech....ayford-focuser/