American Optical Series 35

[dtsh]

Here is an AO Series 35 I picked up some time ago. The serial number indicates it was made in 1951. It is equipped as a monocular with a 3 hole nose which holds 10x, 43x, and 97x oil objectives, the 10x has a removable tip allowing it to work as a 4x as well.

ao35_1.jpg (137.11 KiB) Viewed 2421 times

The blind, drunk ape that was pressed into service to pack it didn't do a very good job and the corner of the stage got chipped up. It doesn't affect the use at least.

ao35_ding.jpg (96.4 KiB) Viewed 2421 times

It came with another eyepiece, it produces a decent image, but has a smaller fov than an AO Cat.146 eyepiece.

ao35_eyepiece.jpg (104.16 KiB) Viewed 2421 times

Illumination is provided by a 15w (GE 13291 / 15S11/102) tungsten filament bulb. The illuminator clips onto the base of the condenser and there's no field iris, so no Koehler illumination; it does have a frosted lens, so at least the illumination is even.

ao35_illum.jpg (87.52 KiB) Viewed 2420 times

ao35_illum_open.jpg (133.89 KiB) Viewed 2420 times

[Sabatini]

Nice

[dtsh]

Thanks Sabatini.

The 35 is designed for 160mm TL 34mm parfocal objectives. The fine and coarse focus work the same as you'd expect from any scope of the era, but the fine focus is spring/gravity loaded and thus a bit less likely to destroy a slide by crushing it with an objective. The focus travel is about 75cm/3inches providing enough room to fit most RMS threaded objectives; however the coarse focus stop would not function as designed with longer objectives since it is intended for 34mm objectives.

Objectives in AO's 160mm line can be had in coated and uncoated varieties, on this one the 10x and 43x are uncoated, the 100x is coated. Early testing shows the 100x delivering very poor performance, so I need to look at that and see if I just need to clean it better or if there's something else goinng on with it. I don't mind using oil objectives, but I think this instrument would be better with 10x, 20x, and 43x, so I will probably swap the 97x out at some point for a 20x in my supply.

[dtsh]

I didn't put a lot of effort into fixing flaws on these images as my intent isn't to show what the best I can do is, but rather to show what to expect from such an instrument.

I took one image of a section of buttercup stem with the 4x (10x objective with the tip removed), but since its a bit fumbly and I don't typically use 4x, I omitted the step from the remaining.


4x

ao35_bc_04x.jpg (61.12 KiB) Viewed 2325 times

10x

ao35_bc_10x.jpg (90.06 KiB) Viewed 2325 times

43x

ao35_bc_43x.jpg (93.69 KiB) Viewed 2325 times

97x

ao35_bc_97x.jpg (95.3 KiB) Viewed 2325 times

[dtsh]

As with the buttercup stem section, not much effort went into fixing flaws on these images as the intent is to show what to expect from such an instrument. I feel the 43x image turned out pretty nice for a single image.

Mosquito wing, likely Aedes vexans, but I wouldn't bet on it.

10x

ao35_wing_10x.jpg (93.73 KiB) Viewed 2325 times

43x

ao35_wing_43x.jpg (100.88 KiB) Viewed 2325 times

97x

ao35_wing_97x.jpg (86.95 KiB) Viewed 2325 times

[dtsh]

Same as the previous, little effort into fixing flaws, only trying to show what to expect.

The label indicates these are, Stauronesis phoenicentron, Gyrosigma attenutatum, Gyrosigma reimerii, Navicula oblonga, Pinnulara nobilis
10x, soo tiny.

ao35_diatoms_10x.jpg (39.71 KiB) Viewed 2324 times

43x

ao35_diatoms_43x.jpg (40.12 KiB) Viewed 2324 times

97x

ao35_diatoms_97x_1.jpg (80.62 KiB) Viewed 2324 times

ao35_diatoms_97x_2.jpg (66.85 KiB) Viewed 2324 times

ao35_diatoms_97x_3.jpg (62.46 KiB) Viewed 2324 times

[dtsh]

97x

ao35_diatoms_97x_4.jpg (69.31 KiB) Viewed 2319 times

[dtsh]

Here's a link to a stacked image of a section of mosquito wing I had imaged earlier when I was playing around with automating focus stacking with a stepper motor.
viewtopic.php?p=117180#p117180