Which AO scope to buy?

[Scoper]

I am considering dipping my toe into the AO/Spencer pond…which AO/Spencer scope would you recommend and WHY?

Thanks for any advice

[apochronaut]

That entirely depends what you want to use it for and what you expect out of it. There is no ready answer for your question. Generally speaking in each era of development and production there were several scholastic models, small lab oriented models, general purpose models and then those of full research capacity or leaning in that direction. After 1962, I think it was when AO acquired C.Reichert they shifted the development of more pure research microscopes to Austria, since labour costs were about 1/2 that of the U.S .
In the infinity era ( 1961 or so forward) there were 3 series of microscopes from the AO factory that one really needs to be concerned with, if you are looking for a full featured microscope. Other models are less capable. Each series existed in a time frame, was discontinued and replaced by another and each has basically two models of importance distinguished only by illuminator output.
1962-1980 Series 10 - of18 and later 20 watt and series 20 of 100 watt. Aside from the wattage, almost all else is identical.
1980-1985 Series 110 of 20 watt and 120 of 100 watt. Aside from the wattage , almost all else is identical.
1985-2001(?) Series 410 of 20 watt and 420 of 100 watt. 5 place nosepiece for the 410 and 6 place removeable nosepiece for the 420. Almost all else is identical. The model ceased production in I think 2001 as I say but I am not 100 % sure. Later ones were branded Leica, as the Leica brand supplanted all of the other 7 cooperators to the merger.
There is some overlap between series as far as fittings and accessories are concerned. Some between the 110/120 and 410/420 due to an identical condenser dovetail and some between the 120/120 and 10/20 due to a common objective formula.

[Scoper]

Thanks for the comparisons.

Is the availability of accessories/upgrades the same for the different product lines?

I often see it stated that accessories are available but when I check Ebay that is not the case.

An example… looking for the parts to upgrade from brightfield to phase for an AO scope… not readily available or inexpensive…so what am I missing?

[apochronaut]

Phase has to have some cost associated with it. All of the phase systems for AO microscopes since 1946 are quite similar in principal. A 5 place carousel condenser with 4 diaphragms and one open port, and 4 phase objectives ; 10X , 20X, 40-43X and 97-100X. For the series 4 (160mm)a phase set up should run about 350.00 for all components. By far the most widely available system is a Dark M system. For the first infinity series system, add about 50.00 but it also could be about the same. The 110/120 system is almost identical, just with a different dovetail on the condenser.Probably looking at about 400.00, maybe somewhat more. The series 400 used the same condenser as the 110/120 but very different 45mm parfocal objectives. Probably 600.00.00 should do it. Phase is escalating in price.
AO only did phase achromats and planachros and neoplans.

[Scoper]

Again thank you for the great responses.

I agree that phase capability does’t come for free.

What has surprised me is that the cost in the used market for different brands is close to what new Chinese phase options are…including that of used AO equipment.

Also the limited selection of the used equipment including phase accessories on markets like Ebay seems to less than I recall in years past.

Am I interpreting the current market correctly?

[PeteM]

I've also seen the prices of used phase scopes rise, particularly for Olympus and Nikon. Zeiss and Letiz are sometimes a relative bargain at under $1K for a complete good condition phase microscope. Reichert MicroStar are another possible bargain, but even harder to find with a full set of phase objectives recently.

That said, there's a used Olympus BHT with an interchangeable nosepiece filled with high-quality phase objectives for a $950 "buy it now" price. While that might have been more like $795 before the last few years' inflation and inflated expectations from sellers - it's a better scope in my opinion (if in good shape) than something like a new $1500 AmScope phase contrast 600 series scope. Better objectives with higher numerical apertures and wider fields of view, better condenser, better focus, better stage, greater upside for upgrades . . . etc.

[dtsh]

I am considering dipping my toe into the AO/Spencer pond…which AO/Spencer scope would you recommend and WHY?

Thanks for any advice

I would start with what you're wanting to get out of it and what your budget will be. If one wants a very nice brightfield microscope for very little, the old black-body monocular scopes can deliver quite nicely for a trivial amount of money. If a person plans to use it for imaging, especially live-viewing, then one can get a lot of performance for very little money.
I like the Series 10 because it has a relatively small footprint with good build quality. My first AO instrument was a 410 with phase that I got for quite a bit less than an import with similar quality, but it took up too much bench space compared with the 10. I think it was a better performing instrument, but the 10 does everything I need in less space. If I had phase for my Series 15, I could probably shelve or sell the 10's and recover a bit more desk space.

Again thank you for the great responses.

I agree that phase capability does’t come for free.

What has surprised me is that the cost in the used market for different brands is close to what new Chinese phase options are…including that of used AO equipment.

Also the limited selection of the used equipment including phase accessories on markets like Ebay seems to less than I recall in years past.

Am I interpreting the current market correctly?

It depends on the particular setup. I would be surprised if one could find a new import scope with plan achromat phase objectives for the price of what one could find an AO system for. I'm not knocking the import stuff, they can produce very good and usable optics at a very reasonable price, but there's more to a scope than just the optics; a good mechanical stage is a pleasure to use, for example. I've seen some very nice import instruments and I've seen some that I wouldn't wish on anyone.

It seems to me that the availability of used phase comes in pulses and you just have to be patient to find a really good deal as units get retired or a collection gets liquidated. Sometimes you just get lucky and an instrument doesn't seem to draw anyone else's interest for some reason.

In the US, I don't think it'd be difficult to assemble an AO10 with phase for less than new, where money savings matters one could likely save a bit more if they didn't require all plan objectives or were willing to accept an instrument that was missing phase wrenches or an APU (I don't see that Amscope even offers an APU/bertrand lens). Missing wrenches or no APU isn't a show stopper, 0.050" allen wrenches and a phase centering telescope serve the same purpose if not as conveniently packaged. That the AO gear holds such a price still I think says as much about the quality of a ~50 year old instrument (not just AO) as it does about the efficiency and precision of asian manufacturing, both can be wonderful if not exactly equal.

If I were to start all over again, I'd certainly go for phase again, but I know it's something that I find useful often enough

[apochronaut]

Again thank you for the great responses.

I agree that phase capability does’t come for free.

What has surprised me is that the cost in the used market for different brands is close to what new Chinese phase options are…including that of used AO equipment.

Also the limited selection of the used equipment including phase accessories on markets like Ebay seems to less than I recall in years past.

Am I interpreting the current market correctly?

If I was looking to buy a phase microscope right now for the first time and did not want to spend a lot I would nab a good series 10 blank stand and build on it. If you wait for a complete perfect phasestar, you might wait a while and the likelihood that the seller isn't going to know what they have and not want a premium for the completeness and condition is low. Buy a good cheap unadorned stand, then find the objectives and condenser and bertrand lens. An AO bertrand lens is possible but there is more awareness about such things now and they are no longer 50.00. However a phase telescope from any maker will do.
There were basically two professional versions of the 10. One was an 18 watt incandescent illumination system and the other a later 20 watt halogen. In my opinion, one is as good as the other with the one difference being that the 18 watt has a small remote transformer. There was also a lesser illuminator, a student version with a simple on off golf ball incandescent bulb for . An important fact is that ALL of the illuminators for the 10 are modular units that fit into the stand with 2 screws, so don't overlook a stand with the student illuminator. If you happen to find a pristine one with a 4 or 5 place nosepiece, you can always swap the illuminator. for one of the others. They are cheap too.
I use an 18 watt incandescent illuminated, blue filtered stand for both dark and bright phase. 5 place nosepiece with a 4X B.F. objective in the 5th hole, that way in addition to the 4 phase magnifications ; 10X, 20X, 40X and 100X, I get 4X, 10X and 20X DF as well with the same condenser. 5 place series 10 nosepiece's aren't the most common but fortunately the 5 place from the series 110/120 fits and they are more common.
A series 10 in phase is hard to beat for value. The planachro dark phase objectives are thinning out but the achro dark phase are just about as good. The bright phase only came as achros and there was 1 B-Minus phase objective; a 100X oil.
Details.
AO series 10 stand..
2 possible illuminstors available for phase. 18 watt incandescent with remote power supply or 20 watt halogen with integrated power supply.
blue filter over illuminator window required always.
eyepieces 2x 10X W.F. cat. # 176 and if wanted 2x 15X W.F. cat. # 184
binocular or trinocular
3, 4 or 5 place nosepiece.
5 port phase carousel condenser housing cat. # 1240. with 4 ( 10X, 20X, 40X and 100X standard working distance ) phase diaphragms required.use for all objectives.
achromat aplanat phase condenser # 1242 standard working distance recommended.
4X .12 cat. # 1075 achromat or # 1017 planachro objective will provide DF when used with the 20X phase diaphragm.
10X .25 cat. # 1224 achromat dark phase, cat. # 1211 planachro dark phase ( 1224 and 1211 are actually the same objective) and cat. # 1234 achromat bright phase.
20X .50 cat. # 1225 achromat dark phase, cat. # 1212 planachto dark phase and # 1235 achromat bright phase.
45X .55 cat.# 1238 achromat dark phase, cat. # 1213 planachro dark phase and # 1239 achromat bright phase
100X 1.25 cat. # 1227 achromat dark phase, cat. # 1214 planachro dark phase , cat. # 1237 achromat bright phase and cat. # 1229 achromat B-Minus Phase
Any objectives can be mixed in a nosepiece with any other and used with the same condenser and the correct magnification diaphragm.