AO 160

[Josephus Miller]

Hi all,

As I explained over here in my introduction, I been working with an American Optical 160. It has performed quite well over the few weeks I've had it. My principal interest is in pond life, and it seems to be well suited.

160.jpg (69.05 KiB) Viewed 2347 times

One feature that I did not know to expect has been the "floating" stage. (Not sure what it's actually called, but that's descriptive enough.) This allows the whole stage to move freely on the X and Y axes. It moves smoothly but with a great deal of friction (perhaps by use of a high viscosity lubricant?). The forces are well balanced to that I can "drive" the slide with one finger on the stage to follow critters easily, even at high magnification. It has plenty of travel, and I run out of sample before I run out of travel. I've encountered mechanical X/Y stages that move by a micrometer screw or similar (good but slow and sometimes awkward), and I've used plenty of instruments where you have to scoot the slide around under the clips to move the sample (not so good--you jitter around a lot). I had never encountered this arrangement before, but it has been the best of both worlds so far!

Objective-wise, it came with the following four: 100x oil immersion, 43x, 10x, and 5x (I think). As you can see from the image below, they have all been well used because the markings are almost completely worn off the outside of each lens (except the 100x). The lowest power objective is the most effaced.

160close.jpg (49.16 KiB) Viewed 2347 times

The only bad things, beside the worn paint on the objectives, are that it doesn't come equipped with any kind of filter drawer or slot in the condenser (that I could find anyway), and that the click stops on the nosepiece are very stiff. This makes it a bit of a chore to swap objectives, but I'm getting used to it.

Any suggestions for getting the most out of this instrument are very welcome!

[Josephus Miller]

Another question:

The objectives shown here have been great so far, but at some point I would like to explore some different options, like a 20x and a 60x. The 60x in particular is attractive, giving a magnification boost without having to monkey with immersion oil.

Unfortunately, I haven't been able to find any infinity-corrected AO objectives in those powers in any of the usual places (i.e., ebay). I've seen reference to them here and there, so I'm pretty confident they do exist, but while there are plenty of the 10x, 43x, and 100x (oil) objectives out there, the 20x and 60x seem to be rare birds. Is there anywhere else I should be looking? Or do I just need to be patient? Alternatively, are there other easier to find makes that could be compatible?

Many thanks in advance!

[GerryR]

You might find it easier to find a 15X eyepiece to get 645X, 150X, and 75X from your 'scope. I believe the 147 and 184 eyepieces are 15X

[Josephus Miller]

You might find it easier to find a 15X eyepiece to get 645X, 150X, and 75X from your 'scope. I believe the 147 and 184 eyepieces are 15X

An excellent idea! And you seem to be dead on with those part numbers. There are several offerings out there--I'll investigate.

[dtsh]

You might find it easier to find a 15X eyepiece to get 645X, 150X, and 75X from your 'scope. I believe the 147 and 184 eyepieces are 15X

The 160 should be an infinity system and use the Cat.176 10x and Cat.184 15x eyepieces. Many of them have a Cat.138 (I don't recall the right Cat.#, but it's a 13?) or similar eyepiece by default which has a narrower field of view, often locked in with a retaining screw on the underside of the tube.

Any of the 34mm infinity series should work in it and I agree that a 15x eyepiece with the 43x Cat.1116 objective is the better performing route to a higher magnification than a 60x and much easier to find.

The general rule of thumb of 1000 X NA as max magnification suggests the CAt.1116 43x with a 0.66NA to be usable up to 660x

@Josepus Miller, you might find this site quite helpful if you haven't found it yet:
https://user.xmission.com/~psneeley/Per ... ctives.htm
https://user.xmission.com/~psneeley/Per ... pieces.htm

There's a lot more there than just these two pages, but I think you will find them to be the most useful.

[Tom Jones]

That floating/grease/glide stage (the real name I think) is wonderful. I didn't know they existed until I found them on some AO Sixties I bought to rehab for a school. They make life a lot easier for students (and the rest of us) to move the slide by grabbing something other than just the slide. Moving the entire stage is much easier to control. You don't see them very often. I'm surprised they aren't on more scopes.

Lomo makes one too. And it's just grease between the stage and the support.

I liked them enough for video I made aluminum ones for my SZH stereo, BHS and BX-40. Nice 360 degree smooth panning.

[Josephus Miller]

The 160 should be an infinity system and use the Cat.176 10x and Cat.184 15x eyepieces. Many of them have a Cat.138 (I don't recall the right Cat.#, but it's a 13?) or similar eyepiece by default which has a narrower field of view, often locked in with a retaining screw on the underside of the tube.

Any of the 34mm infinity series should work in it and I agree that a 15x eyepiece with the 43x Cat.1116 objective is the better performing route to a higher magnification than a 60x and much easier to find.

The general rule of thumb of 1000 X NA as max magnification suggests the CAt.1116 43x with a 0.66NA to be usable up to 660x

@Josepus Miller, you might find this site quite helpful if you haven't found it yet:
https://user.xmission.com/~psneeley/Per ... ctives.htm
https://user.xmission.com/~psneeley/Per ... pieces.htm

There's a lot more there than just these two pages, but I think you will find them to be the most useful.

Dtsh: thank you for the comprehensive reply here. Very helpful! I had encountered some of Mr. Neeley's pages before, but I hadn't seen the eyepiece table.

Here is what I'm working with now on the 160:

IMG_3637.jpg (65.27 KiB) Viewed 2099 times

It's the cat. 138, just as you suspected, and it is held in by a set screw under the tube. I haven't had it out yet, but it looks like it shouldn't be a problem. Interestingly, the table you linked lists the 138 at 6x, even though mine is marked 10x (as you can see above.)

I will look around for a cat. 184 15x eyepiece.

[Josephus Miller]

That floating/grease/glide stage (the real name I think) is wonderful. I didn't know they existed until I found them on some AO Sixties I bought to rehab for a school. They make life a lot easier for students (and the rest of us) to move the slide by grabbing something other than just the slide. Moving the entire stage is much easier to control. You don't see them very often. I'm surprised they aren't on more scopes.

Lomo makes one too. And it's just grease between the stage and the support.

I liked them enough for video I made aluminum ones for my SZH stereo, BHS and BX-40. Nice 360 degree smooth panning.

Yes! I also wonder why these aren't standard equipment.

[GerryR]

The 184 15X eyepiece would be the better option, but the 147 will work if you can' find a 184. See near the end of the following thread for more clarification:
viewtopic.php?f=24&t=19550

[dtsh]

It's the cat. 138, just as you suspected, and it is held in by a set screw under the tube. I haven't had it out yet, but it looks like it shouldn't be a problem. Interestingly, the table you linked lists the 138 at 6x, even though mine is marked 10x (as you can see above.)

The site is a great resource but it is not perfect and there are some errors here and here. It might even be possible there was an older 6x eyepiece that had been designated as a 138, I don't know.
I recommend looking for a 176 10x as well, the field of view will be much wider than with the 138.

[apochronaut]

There may be limitations on the projected f.o.v. of the student grade objectives, thus any extra f.o.v. provided by a # 176 eyepiece might not be very valuable.