Modular high power inverted scope

[zzffnn]

I am looking for a highly modular (DIY friendly) high power inverted scope for live protists.

My rough idea for the optical train (from top to bottom) is:

a very light but powerful LED flashlight fixed onto the pile of inverted scope ->
-> diffusion -> COL (circular oblique light) masks ->
-> regular upright oil (NA 1.25) condenser used upside down (scope fixture should be able to take this DIY), with its top lens immersed in pond water Petri dish (which would provide NA of around 1.1 for circular oblique light) ->
-> about 1.1-1.2 mm thick pond water in Petri dish with DIY cover slip as bottom -> Plan A or Plan B

Plan A -> LOMO short barrel 160 tube length water immersion objectives (modified immersion 11/0.25, 30 / 0.9 iris and 65 /1.1) with water bridge between top lens and cover slip bottom, or 45 mm parfocal 160 tube length oil immersion objective (air 10/0.25, Nikon 50/0.85 and Zeiss 90/1.32) with oil bridge between top lens and cover slip bottom;
-> 160 mm tube length -> eyepieces, preferably a trinocular (scope head should be removable)

Plan B -> AO short barrel infinity oil immersion iris objectives (air 10/0.25, 50/0.85 and 100/1.25 ) with oil bridge between top lens and cover slip bottom->
-> close to AO series 10 infinity tube length -> eyepieces, preferably a trinocular (scope head should be removable)

* A removable head would allow me to DIY add a PZO DIC head, which would be highly useful if I decide to do so in the future.

I prefer smaller inverted scope with fine focus and good mechanical stage for Petri dish. Don’t want to spend a lot for fancy features that I have not listed above, though I don’t have a fixed budget either. I highly prefer to use my existing LED light, condensers, objectives and eyepieces that I have listed above.

Please kindly recommend inverted scope models that suit my needs. I can perform some basic DIY but don’t have a dedicated machine shop. Thank you very much!

I don’t remember if Nikon or AO made an inverted scope with removable head; I do have extra upright heads available for Nikon 160 tube length, AO series 4 (160 mm tube) and AO series 10 (if they are compatible at all).

AO = American Optical (Spencer)

[ldflan]

Water immersion objectives won't perform well in this role, I think. The water will run off the objective too quickly. You have to use a particularly viscous oil for oil immersion on an inverted scope.

While it's possible to do high magnification work with an inverted scope, it's really not their strong suit. Best at 40x-400x with LWD objectives. That said, if you still want to plunge into something... let's see...

I assume you want cheap. The old black Nikon S inverted scope from the 60s fits your specifications pretty well, I think. You can find them for next to nothing. Head is interchangeable with standard Nikon S. They made a long working distance phase contrast condenser that used standard S series objectives (based on the one I have and others seen online). I have a pretty complete parts scope in the basement, I think. PM me if you want it.

[PeteM]

The Reichert Biostar (1820) and the earlier A.O. (1810?) inverted scopes could be an option. Heads interchange on the 1820 so you can match up to your objectives. However, the Biostar is a bit larger. The older A.O. versions I've seen used bolt-on heads similar to those of the Series 150 - and should work with your Series 10 objectives.

Used models sometimes show up with the proper LWD objectives for not too much money.

[ldflan]

I've owned a Biostar. I'd certainly recommend it for someone who wants a working inverted scope with phase contrast that works well at a really cheap price point, assuming you get it with a decent set of LWD objectives and the phase contrast condenser. Good choice for a high school biology class, or home school, or an enthusiast on a budget.

But I think that for DIYing the light source and the condenser, the Biostar is kind of a poor design. It's a halogen bulb fitted to a plastic cradle that slips into the fixed cross bar. You can get inside by opening the top of the bar, but options are limited. The simpler old Nikon and Olympus models had a much more adaptable system overall, I think.

[PeteM]

Agreed - more DIY surgery required for the 1820.

I personally like the Olympus inverted scopes. The smaller CK, CK2, CK40 etc. would be candidates and more suitable if a PZO DIC DIY project was in the future. But to host the A.O. objectives an A.O. head would have to be grafted on. Should something like a CK40 come with the proper Olympus LWD objectives - with correction collars in the better 20x and 40x versions - they're very good.

[ldflan]

I've never used a CK or the later Olympus inverted scopes. One strike against it on the effort to make is a high power scope is that it looks like the light source and condenser of the CK were integrated as one unit, is that right? The old Nikon had a separate and completely independent adjustable condenser mount, which you would need for a high power mod.

[apochronaut]

Why high power inverted? Is not the hallmark of inverted the utilization of gravity : letting gravity bring the subject to the coverslip, rather than away from it?
With high magnification, isn't that coverslip going to get a little crowded?.....especially with the kind of condensers those clunkers are fitted with.

[zzffnn]

Thank you very much, gents.

I have looked at all scope models mentioned herein. Indeed, I would agree that Nikon black inverted scopes are probably my first choice. Idflan, I will send you a private message.

Good point about water running off from inverted objective immersion.

My only question for black Nikons is, if I put an upright NA 1.25 condenser on it, can I lower the condenser top lens enough for it to be immersed under water in Petri dish.

My Petri dish would have DIY cover slip as bottom and hold water level of about 1-1.2 mm thick. So condenser top lens has to go down, and objective top lens has to go up (to almost touch cover slip, which is maybe about 1-1.5mm higher than stage level).

For everything else, such as light fixture, head dovetails size, tube length, I think I can figure out on the black inverted Nikon. I am currently using a Nikon Optiphot as my main scope, which may receive a PZO add-on head unit as permanent mod; dovetails can be made to mate, as I remember.

I think I can make AO 1820 work with my LED light, though its bulk and halogen light source seems unnecessary for my use. Also I am not sure about dovetail: does AO 1820 use the same dovetail as my AO series 10 or AO 60/60/150? Tube length is probably fine, when I add on PZO head unit, since it is adding up two infinity spaces? I also have more 160TL objectives than AO infinity objectives.

[ldflan]

The 1820 properly equipped is a fine scope, but not good for DIY.

The condenser mount for the Nikon is a simple clamp, the diameter being a bit smaller than Zeiss standard. That's going to be important, unless you want to kluge a dovetail on. The AO dovetail is very far from anyone else's... I think the condenser arm should go as far down as you need. I will look at it tomorrow.

For the "petri dish" I would suggest simply buying some cell culture chamber slides made from coverslip glass. They're a bit expensive, but with care can be made to last quite a while.

[zzffnn]

Why high power inverted? Is not the hallmark of inverted the utilization of gravity : letting gravity bring the subject to the coverslip, rather than away from it?
With high magnification, isn't that coverslip going to get a little crowded?.....especially with the kind of condensers those clunkers are fitted with.

Those are surely valid points, apochronaut.

Yes, the cover slip bottom would be crowded if I don’t manually cleanly it up a little bit. But I believe I would be able to manually clean it up (such as cut plants / leaves small and pipette out sand particles), then let protists sit and behave more naturally (than upright scope setting with cover slip pressure and lack of oxygen).

High NA condenser’s top lens can be removed to make working distance longer for such manipulation, along with low power objectives.

[BramHuntingNematodes]

I have an old Zeiss optin-era invertoscop and a few things a like about are that it was very cheap and also I don't feel bad about changing stuff on it as it is not a work of art. A bad thing is rhat Zeiss stuff of many eras often falls apart with age and that includes the prisms in the heads of the opton scopes. Standard heads fit though, which is a big plus.

I can't think of an application that a high power immersion inverted scope that wouldn't be much better treated by car ful isolation and preparation of the sample to be viewed with a usual microscope. These high power objectives require so much delicacy and the right conditions. Right away I'm thinking the lack of slip, or rather the lack of slide, means the samples won't be flat.enough.

[BramHuntingNematodes]

Currently on that.zeiss I have a condenser fork made.from.mdf and the light source is an led and spare condensing lens I had lying around. I like doing that kind of stuff but it's.more.forgivimg on the lower powers

[zzffnn]

………

For the "petri dish" I would suggest simply buying some cell culture chamber slides made from coverslip glass. They're a bit expensive, but with care can be made to last quite a while.

Thank you. I have seen those chamber slides made for 1mm slide, but not those made for 0.17 mm cover slips. Do you see any on eBay, what brand / model I should search for?

[ldflan]

I can't think of an application that a high power immersion inverted scope that wouldn't be much better treated by car ful isolation and preparation of the sample to be viewed with a usual microscope. These high power objectives require so much delicacy and the right conditions. Right away I'm thinking the lack of slip, or rather the lack of slide, means the samples won't be flat.enough.

As to your first thought, in fact anything involving micromanipulation at high power is far better on an inverted scope.

The problem is not "lack of slip" or "lack of slide." You can certainly use both on an inverted scope. The problem with oiling up a slide on an inverted scope is that the oil is thick, and tends to lift the slide unless it is securely clipped down. This is not an issue on an upright stand.

[zzffnn]

I can't think of an application that a high power immersion inverted scope that wouldn't be much better treated by car ful isolation and preparation of the sample to be viewed with a usual microscope. These high power objectives require so much delicacy and the right conditions. Right away I'm thinking the lack of slip, or rather the lack of slide, means the samples won't be flat.enough.

As to your first thought, in fact anything involving micromanipulation at high power is far better on an inverted scope.

The problem is not "lack of slip" or "lack of slide." You can certainly use both on an inverted scope. The problem with oiling up a slide on an inverted scope is that the oil is thick, and tends to lift the slide unless it is securely clipped down. This is not an issue on an upright stand.

This should be manageable in my hands. I am well trained as a wet lab biomedical scientist and can perform related DIY. Using a custom mix of type A and B immersion oil may solve the lift problem. Plus, if I use a Petri dish with DIY cover slip bottom and fill it with water, there should be enough weight to hole the cover slip bottom down.

I should be able to DIY a Petri dish with very flat cover slip bottom.

[ldflan]

[quote=zzffnn post_id=132961 time=1676524904 user_id=315]
Thank you. I have seen those chamber slides made for 1mm slide, but not those made for 0.17 mm cover slips. Do you see any on eBay, what brand / model I should search for?
[/quote]

Search "chambered coverslip" or chambered coverglass. Single well probably be best?

https://gracebio.com/products/cell-cult ... overglass/

[zzffnn]

Definitely. Single well would be the best. But multiple well can work too, if wells are big enough for condenser top to dip in. What I saw online seem too small for condenser dipping though.

[PeteM]

I've never used a CK or the later Olympus inverted scopes. One strike against it on the effort to make is a high power scope is that it looks like the light source and condenser of the CK were integrated as one unit, is that right? . . .

Yes. Pretty easy to separate things though, if equipped with simple tools (bandsaw, drill press) since the mounting of the CK (a rod) is much the same as the early black Nikon. Olympus' IMT and IMT-2 put the condenser on a separate focusing track, but those scopes (while very nice) are massive.

ZZffnn - my take on your quest is that I'd want to have regular LWD objectives with correction collars as well as a regular higher power condenser peering through a cover-slip-bottomed dish. Not so delicate or fussy when scanning for protists, pulling some out of the bath, viewing up to 400x, etc. The long barrel objectives with adjustments for glass thickness tend to be a bit better than the early short barrel versions -- and also have a nosepiece-to-stage distance more suitable for trying different objectives, the PZO DIC etc. Anyhow -- when buying an inverted scope, looking for and getting one with proper LWD objectives probably isn't going to cost that much more than one without.

Perhaps someone like Kurt can chime in on their use cases?

Most of the finite and relatively affordable inverted scopes I've used (Hund Wetzlar, Olympus CK, CK2, IMT-2 . . .) have arms that easily detach with two or three screws. It could also make sense to pull off the arm of whatever you get, set it aside, and put your LED lamp and high power condenser on a new one?

As for changing the heads -- the long barrel Olympus finite inverted scopes (CK2+) have interchangeable heads. Several of the Nikon from that long barrel finite era (ivory colored) have dedicated heads.

If you're looking for just a carcass with interchangeable heads, this Nikon is pretty simple and pretty cheap. I don't know if it, like some Model S upright scopes, suffers from broken plastic fine focus gears. And you might have to shim up the stage to fit DIN standard objectives. https://www.ebay.com/itm/185487458383?h ... 000%7C7000

Note, though, that picking up decent LWD objectives one by one, should you want them, is likely to be expensive.

[Hobbyst46]

May I add something. Just a passing thought...

Confocal microscopes in reasearch labs are often based on top-notch inverted microscopes, to which software and hardware accessories have been added.
The software and accessories of one such microscope that I saw aged and became defunct and outdated. Due to the general deficiency and high prices of maintenance and upgrading,
it lost its confocality value and was "downgraded" and sent to the cell culture lab, where it now serves as general purpose, side by side with Olympus CKs and such.

[apochronaut]

I don’t remember if Nikon or AO made an inverted scope with removable head; I do have extra upright heads available for Nikon 160 tube length, AO series 4 (160 mm tube) and AO series 10 (if they are compatible at all).

The 10/20, 100/110/120 , 410/420 and Biostar 1800 series all used the same dovetail for the head : 2 inch ( 50.4mm), so you could use a series 10 head on a Biostar for instance. It is theoretically possible to use any head on any of those microscopes and preserve planarity and lateral ca corrections by manipulating objective/eyepiece combinations, since the 34mm parfocal corrections are slightly different than the 45mm parfocal corrections and the telan lenses seem so too.
AO was apparently worried that there might be a pandemic of telescopitis in the future and a wave of eyepiece swapping might take hold. In order to curb such a possible outbreak , they made the ocular bores in the 400 series heads 23mm , rather than 23.2mm, so it is really hard to get most eyepieces, other than the #181, 182 and 191 in them. Can be done in some instances. I use #145 eyepieces ( from the Stereostar 580) in a Diastar with Reichert Austria and Nikon objectives(infinity plus some 160 as well) and they are perfectly compensating and can fit but boy are they tight.
The AO inverted microscopes were configured for the 34mm parfocal system. I never saw any other objectives but I have seen a series 400 head on a Biostar, as well as a series 100 head, which mine had. Maybe those series 400 Biostar heads used a different telan lens and had 23.2mm bores because they shouldn't have carried the 23mm diameter # 181 eyepieces but physically they look like regular series 400 heads. I have never had one in my hands that I could verify to have originated in the factory on a Biostar 1800 series, so I don't really know what went on there.
I haven't done an exhaustive switch around of optics and eyepieces with the various objective/head/eyepiece combinations possible. I never needed to but fiddling with a Biostar to up it's magnification potential might pose that requirement.

A couple of other thoughts. The 34mm parfocal requirement puts all those other 34mm objectives on the table. There was a set up catalogued, using the .90 achromat aplanat with the #1867 100X .90 planachro, probably for dried smears. I don't think anything over .90 was ever catalogued for it, nor was the # 1323 40X .80 34mm parfocal planapo. That one would turn the machine around, especially with guaranteed dimension cover glass bottoms. You could do 600X with a very wide flat apparent field with the # 184 15X eyepieces. No immersion required and likely DF too at 600X if you can find a dry condenser with a high enough N.A. that can fit.

With respect to immersion. Have you considered mixing glycerin with water to get some viscosity?

[BramHuntingNematodes]

I can't think of an application that a high power immersion inverted scope that wouldn't be much better treated by car ful isolation and preparation of the sample to be viewed with a usual microscope. These high power objectives require so much delicacy and the right conditions. Right away I'm thinking the lack of slip, or rather the lack of slide, means the samples won't be flat.enough.

As to your first thought, in fact anything involving micromanipulation at high power is far better on an inverted scope.

The problem is not "lack of slip" or "lack of slide." You can certainly use both on an inverted scope. The problem with oiling up a slide on an inverted scope is that the oil is thick, and tends to lift the slide unless it is securely clipped down. This is not an issue on an upright stand.

Well it will be a consideration here because we are talking about manipulating live protists and dipping a condenser into their habitat. In any case you cant both manipulate and have a specimen sandwiched between slip and slide on any scope. It appears as if zzffnn has some specialized training and I have to assume then has some special use case I may not have any experience with.

[ldflan]

I can't think of an application that a high power immersion inverted scope that wouldn't be much better treated by car ful isolation and preparation of the sample to be viewed with a usual microscope. These high power objectives require so much delicacy and the right conditions. Right away I'm thinking the lack of slip, or rather the lack of slide, means the samples won't be flat.enough.

As to your first thought, in fact anything involving micromanipulation at high power is far better on an inverted scope.

The problem is not "lack of slip" or "lack of slide." You can certainly use both on an inverted scope. The problem with oiling up a slide on an inverted scope is that the oil is thick, and tends to lift the slide unless it is securely clipped down. This is not an issue on an upright stand.

Well it will be a consideration here because we are talking about manipulating live protists and dipping a condenser into their habitat. In any case you cant both manipulate and have a specimen sandwiched between slip and slide on any scope. It appears as if zzffnn has some specialized training and I have to assume then has some special use case I may not have any experience with.

I guess I am not following your thought here. You proposed "flatness" as a problem given the lack of a second glass surface. Depth of field is an issue, but at 1000x it's the same issue whether we are talking about a suspended drop or 1/16" of water in a film. Flatness in fact less of a concern on an inverted scope than with a suspended drop on an upright scope because most everything of interest ends up on the bottom surface as a result of gravity. This is where the inverted scope has upright beat --that, and using large containers like petri dishes etc.

[zzffnn]

Bram: sorry I did not make it crystal clear: when I “manipulate”, I would use low power without immersion or sample being “sandwiched” in anyway. After I “manipulate”, I can then switch to condenser immersion and higher NA objectives.

I think idflan understood my idea better, as he probably has done (or thought about) something similar.

[zzffnn]

Thanks, PeteM. I have some short barrel LWD (correction collar) inverted objectives in hand. I would add better long barrel ones in the future if I use them often.

[BramHuntingNematodes]

As to your first thought, in fact anything involving micromanipulation at high power is far better on an inverted scope.

The problem is not "lack of slip" or "lack of slide." You can certainly use both on an inverted scope. The problem with oiling up a slide on an inverted scope is that the oil is thick, and tends to lift the slide unless it is securely clipped down. This is not an issue on an upright stand.

Well it will be a consideration here because we are talking about manipulating live protists and dipping a condenser into their habitat. In any case you cant both manipulate and have a specimen sandwiched between slip and slide on any scope. It appears as if zzffnn has some specialized training and I have to assume then has some special use case I may not have any experience with.

I guess I am not following your thought here. You proposed "flatness" as a problem given the lack of a second glass surface. Depth of field is an issue, but at 1000x it's the same issue whether we are talking about a suspended drop or 1/16" of water in a film. Flatness in fact less of a concern on an inverted scope than with a suspended drop on an upright scope because most everything of interest ends up on the bottom surface as a result of gravity. This is where the inverted scope has upright beat --that, and using large containers like petri dishes etc.

The two surfaces exert a flattening effect. A nematode crawling about the bottom of a dish has much more height than when between two glass surfaces. I have difficulty with high power objectives and so I try to take every slight advantage

[ldflan]

He's after protists, not nematodes. If you are flattening your nematodes between glass, that's fine but I don't understand it to be the point here.

[BramHuntingNematodes]

Ok then well a protist will also have more height when crawling along the bottom of a dish. We're talking fractions of a micron when using immersion objectives

[zzffnn]

It is always a compromise and depends on the protists species and behavior, Bram. Chances are higher when gravity is on my side.

I simply want to have more options at my disposal than the standard typical (which I already have), and I am happy to go back to the standard typical approach when necessary. I understand I am not doing the standard typical inverted scope work here.

Pond dipping an upright condenser top lens, on inverted scope, to increase NA and magnification, surely sounds a little crazy. But hey, I have quite a few extra condensers to mess around, so no worries even if I destroy them. Many of them have removable top lens that can be cleaned when necessary.

[BramHuntingNematodes]

I believe it and am always in favor of empirical investigation of new techniques. In fact, the limitations of hwd condensers has prevented me from doing a lot high power work on the old invertoscop, so I would be interested if you find success with this approach.

[ldflan]

Ok then well a protist will also have more height when crawling along the bottom of a dish. We're talking fractions of a micron when using immersion objectives

Fractions of a micron are my point. I'm not a pondwater guy, so this is outside my area of direct knowledge. But you're not going to squeeze the protists down that much. Most are too small. And at least from what little I have seen, there are pretty profound behavioral differences between nematodes and protists that seem like they could make all the difference. There is also an entire order of magnitude difference between the size of the very smallest nematode and the average protist, so the motion effect you probably get at high powers with a subject 100x larger is probably profound. Again that's just my guess, as I don't do much pondwater gazing. To give the idea a chance of working, I think I would certainly want to slow everything down as best I could with cold or a thickening agent.

Also, zzffnn, you may want to consider using a layer of mineral oil over your sample to reduce evaporation.