Wanted: 0.5 Barlow lens for AO 569 stereoscope

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Tombk
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Joined: Sun Jul 04, 2021 9:33 pm

Wanted: 0.5 Barlow lens for AO 569 stereoscope

#1 Post by Tombk » Thu Jul 08, 2021 12:59 pm

Hi all, I’m looking for an 0.5 Barlow lens for my American Optical 569 Starzoom 0.7-3 scope.

apochronaut
Posts: 6272
Joined: Fri May 15, 2015 12:15 am

Re: Wanted: 0.5 Barlow lens for AO 569 stereoscope

#2 Post by apochronaut » Thu Jul 08, 2021 2:35 pm

There are 2 of those. Cat.# 575 will be marked on the barrel of one of them. It is quite long compared to all the other aux. lenses, almost 2". It has a 5.7" working distance.
The other one is a special order .5X with an 8" working distance. The cat. # is K2595. K numbers were usually reserved for special purpose accessories and are not often marked on the part, probably because there were no blanks made up. The # would have had to have been hand stamped. Not a good idea on a lens housing.It is shorter, maybe about 11/16" deep and resembles the .3X but the .3X will be marked as such with #573 additionally.

There are also many more Cycloptic aux. lenses out there and they superficially resemble those for the Stereostars. Most are marked with a catalogue number but a few are not. The Cycloptic lenses have a smaller thread, 1 13/16" diameter.

The Stereostar thread is 1 7/8", which is very close to 48mm, about 1/3mm short. 48mm is a kind of standard size for stereo aux.lenses. I rechecked the stereostar thread and I can run a 36 t.p.i. gauge around the perimeter. Neither a 32 t.p.i. or M .75 will, so I would say it is 1 7/8" X 36 t.p.i.. However, in a pinch the M48 X .75 .5X lens could probably be made to thread on enough to work, so depending if you can find an AO one, those Chinese ones aren't expensive.
Anyone tried one of those?

dtsh
Posts: 977
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Location: Wisconsin

Re: Wanted: 0.5 Barlow lens for AO 569 stereoscope

#3 Post by dtsh » Thu Jul 08, 2021 3:46 pm

apochronaut wrote:
Thu Jul 08, 2021 2:35 pm
The Stereostar thread is 1 7/8", which is very close to 48mm, about 1/3mm short. 48mm is a kind of standard size for stereo aux.lenses. I rechecked the stereostar thread and I can run a 36 t.p.i. gauge around the perimeter. Neither a 32 t.p.i. or M .75 will, so I would say it is 1 7/8" X 36 t.p.i.. However, in a pinch the M48 X .75 .5X lens could probably be made to thread on enough to work, so depending if you can find an AO one, those Chinese ones aren't expensive.
Anyone tried one of those?
I ran some numbers and 36tpi seems to be a close match for 0.7mm pitch (36TPI = 0.706mm), which is probably close to tolerance. M48 as you mentioned looks to be a tolerable match for 1-7/8", but I don't expect much likelihood of finding a compatible lens threaded for M48 with a 0.7mm pitch. I don't think 0.7mm pitch is used much outside some of the small metric bolts.

Scarodactyl
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Re: Wanted: 0.5 Barlow lens for AO 569 stereoscope

#4 Post by Scarodactyl » Thu Jul 08, 2021 5:44 pm

0.75mm would be standard for optics though not universal. I've had instances where 0.75 mm threaded fine into 0.70 MM, and instances where they did not.

dtsh
Posts: 977
Joined: Wed May 01, 2019 6:06 pm
Location: Wisconsin

Re: Wanted: 0.5 Barlow lens for AO 569 stereoscope

#5 Post by dtsh » Thu Jul 08, 2021 7:45 pm

Scarodactyl wrote:
Thu Jul 08, 2021 5:44 pm
0.75mm would be standard for optics though not universal. I've had instances where 0.75 mm threaded fine into 0.70 MM, and instances where they did not.
0.75mm pitch correlates pretty close to 34tpi (34tpi = 0.747mm / 0.75mm = 33.87tpi) (apologies if this is just noise).

If one could find a compatible lens and has access to, or friends with, machining equipment (3D printer, possibly?), it shouldn't be a difficult task to create a mount/holder/barrel for it. The effort required may well exceed the value, but different people have different measures of what's reasonable. I've had poor luck making fine threads with 3D printing, but I have had reasonable luck making tight interference fits and using the threads to "cut" into and hold onto the plastic; it usually involves some sanding and fitting of the 3D printed part. I have a holder for a Cycloptic 2x barlow that works that way.
I'm certainly not suggesting this as a good option, but if one can't find the correct part and really wants the functionality badly enough it may be a solution.

Scarodactyl
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Re: Wanted: 0.5 Barlow lens for AO 569 stereoscope

#6 Post by Scarodactyl » Thu Jul 08, 2021 8:31 pm

I have gotten threads down to 0.5mm pitch to work with 3d printing (for a Nikon trinoc head). They jst have to be dialled in, and internal threads have to be oversized a bit since they print tight.

Tombk
Posts: 14
Joined: Sun Jul 04, 2021 9:33 pm

Re: Wanted: 0.5 Barlow lens for AO 569 stereoscope

#7 Post by Tombk » Thu Jul 08, 2021 9:30 pm

Scarodactyl wrote:
Thu Jul 08, 2021 8:31 pm
I have gotten threads down to 0.5mm pitch to work with 3d printing (for a Nikon trinoc head). They jst have to be dialled in, and internal threads have to be oversized a bit since they print tight.
Interesting. Do you print your own 3D stuff, or do you commission somebody else to do it? On another front, if you're still interested in selling that rusted 577s lens you have, I'm interested.

Scarodactyl
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Joined: Sat Mar 03, 2018 9:09 pm

Re: Wanted: 0.5 Barlow lens for AO 569 stereoscope

#8 Post by Scarodactyl » Thu Jul 08, 2021 9:47 pm

I won't sell it but I'd send it for the cost of shipping, probably like 5 bucks. Some cleanup, knock out the corroded lenses and it should be good to go. Shoot me a pm with a paypal address.
I print them myself on my ender 5.

apochronaut
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Joined: Fri May 15, 2015 12:15 am

Re: Wanted: 0.5 Barlow lens for AO 569 stereoscope

#9 Post by apochronaut » Thu Jul 08, 2021 10:48 pm

If you use a barlow. You can clamp your ringlight directly onto that but obviously will need the 577 blank otherwise.

There are two incarnations of the M48X .75 barlows available.
https://www.ebay.com/itm/273469486556?_ ... %3A2047675

This one has a slightly longer W.D. but both are over 6" This appears to be the same one Amscope sells at twice the price and oddly gives a thread diameter of both
1 7/8" as well as 48mm. Running a .75 mm thread gauge into the female thread of a 570 , the gauge started to bind about 1/3 of the way around. With the extra leverage provided by the lens housing it will probably go on 1/2 turn or a little more, so about 1/2 way to lock. A lens with the correct thread turns 1 1/3 turns to lock.

https://www.ebay.com/itm/274333279910?_ ... %3A2334524

Scarodactyl
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Re: Wanted: 0.5 Barlow lens for AO 569 stereoscope

#10 Post by Scarodactyl » Thu Jul 08, 2021 11:54 pm

Just did a test on a bad 569 I forgot I had. An olympus 48mm 0.5x doesnt quite thread on, but a 48mm plastic ring light adapter that came with a ring light did thread on with a little effort. That would probably be much better than having to modify the broken auxiliary lens ane I can send it for the same price.

Tombk
Posts: 14
Joined: Sun Jul 04, 2021 9:33 pm

Re: Wanted: 0.5 Barlow lens for AO 569 stereoscope

#11 Post by Tombk » Fri Jul 09, 2021 12:42 am

Scarodactyl, I had bought a ring light with a plastic 48mm ring, that kept popping off when I tried to screw it in place. But I hadn’t tried to wrestle it into place until I read your last post. I was worried about damaging my scope. But having heard that you used “a little effort” to attach what sounds like a similar adaptor, I tried a bit harder and was able to get it on far enough to stay in place and hold my ring light! If I pull on it with any force, it pops off, but it’s firm enough to hold the ring light.

Thank you all for your suggestions. I’ll try to take a picture and post it.

Tombk
Posts: 14
Joined: Sun Jul 04, 2021 9:33 pm

Re: Wanted: 0.5 Barlow lens for AO 569 stereoscope

#12 Post by Tombk » Fri Jul 09, 2021 12:55 am

Here are some pics
Full scope .jpeg
Full scope .jpeg (133.71 KiB) Viewed 4032 times
A close up of the ring light
A close up of the ring light
Close up of light ring.jpeg (104.15 KiB) Viewed 4032 times

Scarodactyl
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Re: Wanted: 0.5 Barlow lens for AO 569 stereoscope

#13 Post by Scarodactyl » Fri Jul 09, 2021 1:07 am

Excwllent, I'm glad that worked!

apochronaut
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Joined: Fri May 15, 2015 12:15 am

Re: Wanted: 0.5 Barlow lens for AO 569 stereoscope

#14 Post by apochronaut » Fri Jul 09, 2021 2:02 am

That's a good start. How does the .5X barlow fit into the picture?

Tombk
Posts: 14
Joined: Sun Jul 04, 2021 9:33 pm

Re: Wanted: 0.5 Barlow lens for AO 569 stereoscope

#15 Post by Tombk » Fri Jul 09, 2021 1:55 pm

apochronaut wrote:
Fri Jul 09, 2021 2:02 am
That's a good start. How does the .5X barlow fit into the picture?
Oops. I posted that in the wrong thread. Nothing to do with the Barlow. My bad.

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