AO 1240 phase condenser (for model 10) on 110

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farnsy
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AO 1240 phase condenser (for model 10) on 110

#1 Post by farnsy » Sat Apr 17, 2021 9:00 pm

I'm looking to add phase contrast to my American Optical 110. I have the 40x phase objective (#1213) and the aperture viewing unit in place. I also have 2 working phase condensers, but they are both #1240/#1242, which was designed for the series 10. The phase turret for the 110 is #1205 or #1206, from my online research (see a snip from the 110 catalog below). I would think the #1240/#1242 would work fine, optically. But physically there is a problem.

I can fit regular 10-series condensers on my 110, so I thought these cat #1240's would transfer over easily, but the yoke seems to be just a little too thick for the dovetail on the #1240/#1242. There's a lip on the #1240/#1242 with the centering screws that is in the way (the space indicated in red in the picture is too small). I'm not seeing any #1205 or #1206 phase turret available for sale and it seems a shame to be shopping around for a phase turret when I already own two in good condition.

Is there a hack to get the 10-series condenser to fit into and work well on an AO 110 microscope? Can the yoke be stolen from a 10 series? Or can the 110 yoke be ground down? Or perhaps the #1240 dovetail can be changed out or modified? Perhaps there is another phase turret that can be easily acquired and will work with the 110 yoke and AO phase objectives? Really appreciate any advice you may have.

My other thought would be to move everything back to one of my series 10 units--I actually have an aperture viewing unit for a 10 series as well--but my 110 is in really good condition and has a analyzer attachment I like, which won't fit on a series 10, sadly. I would prefer to have everything on my 110 and then get rid of all my series 10 units if I can. Ideas?

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dtsh
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Re: AO 1240 phase condenser (for model 10) on 110

#2 Post by dtsh » Sun Apr 18, 2021 1:20 am

The dovetail on the 10 and the 110 are slightly different, with the 110's dovetail being slightly wider at it's narrowest point. Also, the connection point that keys the condenser to the fork is different on the 10 vs the 110; on the 10 is is a slot and on the 110 is is a peg. I have both a 10 and 110 and the 10's condenser does fit in the fork of the 110, but without the pin, it can rotate. I can center it and it appears to work OK. With the phase condenser turret, does it not center even if it doesn't key in?

As I have condensers for both, if some measurments or pictures might help I could provide those. Mine are the aspheric condenser, not the phase contrast, but in regard to the mount that shouldn't matter.

eward1897
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Re: AO 1240 phase condenser (for model 10) on 110

#3 Post by eward1897 » Sun Apr 18, 2021 1:28 am

There is a section on "Condenser Fork Mount Changes" on the PS Neeley xmission site, explaining the compatability issues and some suggested fixes. (Google search for it).

I once had an older AO Spencer phase condenser mounted on an an much more recent Reichert/AO Microstar IV (aka 410). The older thinner fork I needed had different a different mounting hole pattern and didn't fit the 410. But I discovered the dovetail on the condenser focus mechanism was compatible and mounted the older fork and condenser rack successfully onto the 410.


Good luck.

farnsy
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Re: AO 1240 phase condenser (for model 10) on 110

#4 Post by farnsy » Sun Apr 18, 2021 2:34 am

Follow up: I have a spare 110 body and 10 body, so I decided to do some experimenting.

It looks like I can take the entire fork off of the 10 and it will fit into the slot for the 110. It seems to move up and down OK. I'm not sure if it will be positioned in the right place, but at least it will kind of cobble together. That might be the path of least resistance. Tonight I will attempt to move a series 10 onto my real 110 microscope and see if the light path is in the right place. Unfortunately, these 10-series forks are not as good because they can't center.

I would really rather replace the dovetail portion of the 1240 body than move the fork over. I haven't figured out how to dig into that far enough to see if that's feasible yet. Too scared of breaking something. At least I have a spare, right?

Another problem has arisen, though. I checked and it looks like both of my phase condensers are outfitted with 45X annuli. Do you think they will still work with a 40X objective? Probably not, right? At least 45X dark phase objectives are plentiful on the used market.

dtsh
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Re: AO 1240 phase condenser (for model 10) on 110

#5 Post by dtsh » Sun Apr 18, 2021 4:22 am

farnsy wrote:
Sun Apr 18, 2021 2:34 am
Follow up: I have a spare 110 body and 10 body, so I decided to do some experimenting.

It looks like I can take the entire fork off of the 10 and it will fit into the slot for the 110. It seems to move up and down OK. I'm not sure if it will be positioned in the right place, but at least it will kind of cobble together. That might be the path of least resistance. Tonight I will attempt to move a series 10 onto my real 110 microscope and see if the light path is in the right place. Unfortunately, these 10-series forks are not as good because they can't center.
I glanced at it, but it didn't seem the fork would have the right centering and without a centering fork it might be difficult.
farnsy wrote:
Sun Apr 18, 2021 2:34 am
I would really rather replace the dovetail portion of the 1240 body than move the fork over. I haven't figured out how to dig into that far enough to see if that's feasible yet. Too scared of breaking something. At least I have a spare, right?
I haven't looked at the dovetail on the PC condenser, but the aspherics appear to have the dovetail machined in rather than as a separate part. Does it not fit well enough as-is? Certainly a dedicated person could make it fit if it doesn't, but there are probably easier options.
farnsy wrote:
Sun Apr 18, 2021 2:34 am
Another problem has arisen, though. I checked and it looks like both of my phase condensers are outfitted with 45X annuli. Do you think they will still work with a 40X objective? Probably not, right? At least 45X dark phase objectives are plentiful on the used market.
Do you know which annulus the 40x was designed for? The pdf catalog I have here lists the 1249 annulus for the 45x (presumably the same for 1238 and 1239).

farnsy
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Re: AO 1240 phase condenser (for model 10) on 110

#6 Post by farnsy » Sun Apr 18, 2021 5:39 am

Do you know which annulus the 40x was designed for? The pdf catalog I have here lists the 1249 annulus for the 45x (presumably the same for 1238 and 1239).
The wording of this suggests that it's not really possible to use an annulus that's designed for a different objective...the power isn't even exactly the same. I'm going to take that as a "probably it won't work."

My 40X objective is cat 1213. I'm rooting around and not immediately seeing which annulus would be right for this. Ebay has an annulus for 40X but it's an intermediate distance one...I guess that means you don't bring the condenser too close under the slide--I'm not sure how appropriate that is. Alternatively, I could buy a 45X dark phase objective, though it won't be the nice plan achromat.

Or I could wait until I can find a 110 series phase condenser. They just don't seem to come up that often, sadly.

*sigh* I could also give up on the project of combining these microscopes. I have a 10 series with an aperture viewer that I could use. I could even get more (old-school) phase objectives for it and have a 10, 20, 45, and 100 phase scope separate from my brightfield scope. I was kind of hoping to get down to one one microscope, though.

It's kind of a never-ending journey with these AO scopes. Well, the scopes and my OCD-esque desire to have one scope to rule them all.

PeteM
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Re: AO 1240 phase condenser (for model 10) on 110

#7 Post by PeteM » Sun Apr 18, 2021 6:35 am

There is just enough metal in the older too-tight phase condenser to open up the width to get a fit from series 10 through 110 and 410. That will require a metal lathe and a tool able to reach into the recess.

You can also reduce the thickness of the condenser holder "fork" on the target microscope - maybe split the difference between opening up the condenser dovetail width and thinning the fork. Simpler tools, but if you change the fork appreciably the proper condensers won't fit as well.

The rear centering locator is different (if memory serves) and needs to be replicated for the target microscope. You may end up with a double set of condenser centering screws (one set in the older phase condenser and another set on the newer forks), but it can be made to fit.

Don't recall the annulus match or mismatch between 40x and 45x phase objectives and annulli. Might well be close enough to get at least some contrast.

farnsy
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Re: AO 1240 phase condenser (for model 10) on 110

#8 Post by farnsy » Sun Apr 18, 2021 8:50 am

Thanks, Pete.

If I were to transplant the (10 series) fork to my target (110 series) scope, so that it will definitely fit the (10 series) phase condenser, do you think that phase condenser would be fine for everything? In other words, do you think a #1240/#1242 phase condenser compares reasonably well with a #1087 for brightfield? Actually, the top parts are interchangeable. Would it work and improve things to move the #1087 or some other aspheric cap to the phase condenser? Deep questions, I know, but if anyone knows, it's the folks here.

I don't currently have a darkfield condenser, so I wouldn't need to use any 110 series condensers. Actually, if I could find a darkfield condenser, it would probably be from a 10 series anyway.

apochronaut
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Re: AO 1240 phase condenser (for model 10) on 110

#9 Post by apochronaut » Sun Apr 18, 2021 4:49 pm

occasional 1240 condensers will slide into a series 100 yoke and locate by friction rather than by registration, since both the condenser and yoke will have registration grooves, rather than pins. the fit is tight and will work o.k. you can encourage a fit with a file. however, fit is only one of the aspects of achieving perfect phase performance. you are starting with common objectives and annular diaphragms between the two microscopes, so that much is also covered. one other thing on the list is the focal distance of the condenser both at the condenser diaphragm plane and at the field diaphragm plane.

using a #1087 condenser might be a good option but it probably will need slight shimming so as to obtain correct front focus on the diaphragms and or clear the rotary carousel when tightened down. that will somewhat shift it's conjugate focal plane at the field diaphragm. it should produce a good Köhler illuminated field, nevertheless. only it's performance as a dry phase condenser might need evaluation against a 1242 but my recollection is that it is pretty equivalent.

the 1242 is an achromat aplanat type with an N.A. of probably 1.3 when oiled ( at least 1.25) and about .90 when dry. i disassembled one once and did some testing on it , comparing it to a 1201 and a 1087 and that was my assessment at the time. it has the potential of possibly being slightly advantageous irregardless, it probably will perform at least as good as the 1087, except when it comes to where it's front focal plane lies. fortunately it has the possibility of having two front focal planes conjugate with the field plane due to it being provided with an auxillary front lens. used on a series10 with a very short distance to the field plane the aux. lens is left in. when used in a series 20 with a field plane farther away, the lens is removed. i would think that the 110 focal distance would be closer to that of the 20.

i wonder why you don't just use the phase system in a 10? i haven't found the performance of the 110 to be sufficiently better than a properly adjusted 10. the field of view is a little better, that's about all.

dtsh
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Re: AO 1240 phase condenser (for model 10) on 110

#10 Post by dtsh » Sun Apr 18, 2021 8:59 pm

farnsy wrote:
Sun Apr 18, 2021 5:39 am
Do you know which annulus the 40x was designed for? The pdf catalog I have here lists the 1249 annulus for the 45x (presumably the same for 1238 and 1239).
The wording of this suggests that it's not really possible to use an annulus that's designed for a different objective...the power isn't even exactly the same. I'm going to take that as a "probably it won't work."
I've done a little more reading and the 110/120 PhaseStar manual lists 1255 as being the 40x standard phase annulus, so it's not the same as for the 45x.

As usual, psneeley's site is pretty handy.
https://user.xmission.com/~psneeley/Per ... oscope.htm and linked directly from there is the AO 110 PhaseStar catalog https://user.xmission.com/~psneeley/Per ... atalog.zip

That's where I got the reference for which phase annulus goes with the 40x.

farnsy wrote:
Sun Apr 18, 2021 5:39 am
Or I could wait until I can find a 110 series phase condenser. They just don't seem to come up that often, sadly.
It was mentioned to me when I was looking for PC that it's usually cheaper to find an instrument with PC already than it is to hunt up the parts separately. There was a nice AO 10 PhaseStar that sold a few months ago for a song, I really wish I had bid on it. I've seen a couple pop up in the past year, but I agree that it isn't very common.
farnsy wrote:
Sun Apr 18, 2021 5:39 am
I have a 10 series with an aperture viewer that I could use. I could even get more (old-school) phase objectives for it and have a 10, 20, 45, and 100 phase scope separate from my brightfield scope. I was kind of hoping to get down to one one microscope, though.
That's what I would do. It sounds like you have a nearly complete setup already, or at least the harder to find parts.
farnsy wrote:
Sun Apr 18, 2021 5:39 am
It's kind of a never-ending journey with these AO scopes. Well, the scopes and my OCD-esque desire to have one scope to rule them all.
I tried that, but I just don't think it's practical to keep swapping parts in and out, it seems whatever I'm wanting to use isn't currently setup, so I've settled on having different scopes for the functions I use and leaving it at that. One can use PC objectives without the annulus in place as brightfield if you're really sold on keeping just one.
apochronaut wrote:
Sun Apr 18, 2021 4:49 pm
i wonder why you don't just use the phase system in a 10? i haven't found the performance of the 110 to be sufficiently better than a properly adjusted 10. the field of view is a little better, that's about all.
That's what I would do, though admittedly I prefer the series 10 for it's smaller footprint so I am biased.

farnsy
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Re: AO 1240 phase condenser (for model 10) on 110

#11 Post by farnsy » Mon Apr 19, 2021 12:43 am

Thanks for your insights, Apo and dtsh.

Apo, those are some interesting concerns about the ability to get good phase contrast in a microscope for which the condenser was not designed. It seems this is a more complex issue than I had originally envisioned. You sort of suggest the idea of keeping my phase stuff in a 10-series microscope and keeping the 110 for brightfield, which is a good idea. I have a preference for putting everything all in one scope, I guess for table space primarily (I keep it in my bedroom), but that may not be sufficient reason. The other interpretation of your suggestion would be combine everything into a 10-series and get rid of the 110. That's possible since my analyzer and aperture viewing unit will fit on a 10 series. Also a really good idea.

I do have a preference for my 110 over a 10 series. Not because I have a problem with the 10 series in general, but because my 110 is in great condition. It looks great and functions great. Every element of it is clean and nice, almost like when it was first new. There are no artifacts in the light path from random scratches, etches, or debris. It's just a nice scope. I have several 10 series microscopes and they all have significant issues. Dirt in the head or other places where I can't get to it--or it's made of something that doesn't come off easily. Alignment issues that I haven't been able to figure out. Damage to optics, mirrors, or other parts. Issues with the power. There's no question that someone with a little skill could put together probably several good microscopes from what I have and get them dialed in to function very well. I have made an attempt at this, but unfortunately I'm not great at it. I have corrected pretty much all the problems with gears and I have moved the best nosepieces and objectives, but I can't even seem to get things clean enough that I can get what I consider a clean, satisfying, view. The trinocular heads, in particular, are really daunting to mess with--that hole in the top is a magnet for contamination (the 110 has the original cap that goes on the trinocular port and I think it was always used). I'm sure with some more work and research, it could have good success here, but opting to just use the nice microscope is really tempting. That's my initial justification, but it's not fully decided--everything's still on the table.

In view of this discussion, though, I think it might make sense to have a second microscope specifically for phase. In that case, I can buy some more phase objectives and have phase at a bunch of magnifications instead of just 40x or 45x. The phase microscope will be a project for a while, but that has its own rewards.

By the way, you guys are totally right that the cheapest way to get good parts is to buy whole scopes and take what you want from them. I'd be more into that if I was more efficient at getting rid of parts. What I really need to do is disassemble all my stuff, take every part I don't have a use for, and sell it as a separate item on ebay. Just a matter of time and motivation keeping me from that, I guess. Unfortunately the market for local pick up sales (craigslist/offerup) isn't great for AO microscope sellers and I also don't relish the idea of shipping heavy, whole microscope bodies.

My last alternative, still on the table, is to get rid of all this used stuff and buy a new microscope, configured as I want it. I can't spring for the really high-end stuff, but I could see spending $4k-$5k on a nice scope. You can get an Olympus CX43 with phase and polarization for about $5K. I've also been thinking about AccuScope's EXC-500, which is supposed to be kind of an ersatz higher end Nikon (like an eclipse Ci) with compatible, and perhaps competing optics--not sure what the final price will be on that. I gather that their EXC-400 is something similar, but compatible(ish) with an olympus BX and it seems to be attainable. You can get a lot of Motic for that price as well, though Motic doesn't seem to have a ton of fans here as a substitute for a top 4 brand. A new microscope is kind of a different topic but I'd be interested in your input if you have any opinions to share.

Lots of things to think about. Appreciate all the perspectives and info I'm getting here.

apochronaut
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Re: AO 1240 phase condenser (for model 10) on 110

#12 Post by apochronaut » Mon Apr 19, 2021 12:03 pm

I would set up one of the series 10 microscopes for phase, if I were in your shoes. Spend the time to clean and properly adjust one. A push pull type cork, the kind with the plastic knob glued on will work for the trinocular cover or pick up one of the photo tubes on line. The knock off ones may still need some flocking to work the best but I'm guessing the maker has observed logic and improved them by now. They can be made to work well, nonetheless.
That would mean that you would have a nice 110 for BF. For quality observation, you will need a dedicated set of BF objectives, which I assume you have. Keep looking for a set of 10X .30 and 40X .80 planapos . They are uncommon but do show up every now and then and for what they are, are usually priced too low. Way lower than planapos from other mfg. and the quality of the image is indistinguishable.

the ACCU-Scope 5000 is an upgrade on the Nikon C-200. Nikon seems to have deliberately put a limit on how far you can go with that model but the Chinese mfg. of it has not, so a complete set of plan fluor optics, DIC, fluorescence, oil and dry DF ( with planachro only at 100X), 100 watt illumination, 7 place nosepiece ,etc. are all available. They also have 20 and 40X
planapos at the moment but being new objectives, even though they are of Chinese mfg., they are pretty pricey, although significantly less than if they had Nikon or Olympus pasted on them. A full bore system is not cheap either. ACCU-Scope is probably not the best place to buy one, since they have a significant markup on it. It can be bought closer to the mfg. however, as can all the accessories and upgrades for less.

farnsy
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Re: AO 1240 phase condenser (for model 10) on 110

#13 Post by farnsy » Mon Apr 19, 2021 6:27 pm

Thanks Apo. Very helpful as always. My current objectives there are #1017, #1019, #1022, #1023, and #1311. They are all plan but they seem like the standard set that came with every 110 series--nothing special. I bought a #1309 but sadly something's wrong with it (probably oil invasion).

I am having a hard time finding information about the Nikon C200. Did you maybe mean e200? Or the current Ci series (Ci-s?). Could also be that it was discontinued and didn't leave much of a web presence.

apochronaut
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Re: AO 1240 phase condenser (for model 10) on 110

#14 Post by apochronaut » Mon Apr 19, 2021 10:35 pm

Yes, my mistake. E200 it should have been.

arb566
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Re: AO 1240 phase condenser (for model 10) on 110

#15 Post by arb566 » Sun Apr 25, 2021 10:16 pm

Is there any more info available on the 10X and 40X apos'? (cat# etc.) I've not seen them listed anywhere but they sound interesting!
Al.

apochronaut
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Re: AO 1240 phase condenser (for model 10) on 110

#16 Post by apochronaut » Sun Apr 25, 2021 11:15 pm

arb566 wrote:
Sun Apr 25, 2021 10:16 pm
Is there any more info available on the 10X and 40X apos'? (cat# etc.) I've not seen them listed anywhere but they sound interesting!
Al.
send me a p.m. I might have something for you.

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