MicrobeHunter.com Microscopy Forum

Hi All,

I just bought an AO 569 on ebay to look at miscellaneous stuff (bugs, plants, etc.) with my young daughter. The scope itself it great (better than the relatively expensive Scienscope Olympus SZ knockoff here at work), but of course the accessory lenses are no longer available and are hard to find on ebay. I'm thinking right now I just want to get a cover for the objective that also functions as a mount for a ring light. Does anyone know what the thread is and whether it is compatible with any chinese made accessories? Or maybe compatible with Bausch stereozoom?

As an alternative I may forgo the cover an use an led flashlight mounted in the tapered AO starlite mounting hole.

Nick

I don't think they are compatible, but the AO Cycloptic aux threads appear to be 1-3/8 32tpi.
I doubt you'll find anything compatible among the more modern stuff as it is going to be metric, but there are occasions when a metric part and a US Customary part are interchangeable.
(Edit: 32tpi does map well to a 0.8 metric thread pitch, but M35 would be the closest match and the min/max diameter only overlap at the smallest diameter, so very unlikely to work.)

The flashlight would probably work for illumination and be the most inexpensive solution. I use a dual gooseneck (2x 3w LED) and like it, but it wasn't inexpensive.

Congratulations on getting that nice scope.

Ikea and many others make affordable LED gooseneck lamps that work well. The ability to put your light from nearly above to a grazing angle actually works better than a ring light for many purposes.

Dropping the right diameter LED flashlight into the illuminator hole is also simple and convenient. A thick O-ring might help you hold it in place.

Thanks Pete. The scope is in excellent condition and I'm really happy with it. The o-ring is a good idea, although I was actually thinking of machining the flashlight to fit the taper.

dtsh, it's definitely not 1 3/8ths. I measured it with a yard stick and it's more like 1 7/8ths. I will try to measure the threads more carefully tonight.

I'll measure one later this evening. I'll also check how well a third prty one works handholding it onto the threads, havwn't tried that before.

Scarodactyl, I beat you to it. I brought home some calipers and thread gauges, as well as a 48mm Barlow.

As far as I can tell, the AO is 1 7/8ths thread with 32 threads per inch. I tried threading the 48mm/0.75mm pitch Barlow and it unfortunately does not fit. The 48mm is only 14 thousands larger in diameter, and the thread pitch is surprisingly close, however no cigar.

Scarodactyl wrote: ↑

Sat Sep 25, 2021 1:26 am

I'll also check how well a third prty one works handholding it onto the threads, havwn't tried that before.

I'm curious about this aspect, I think if one could find a compatible lens optically, it shouldn't be too difficult to machine or 3D print something to adapt it to the scope. I can't be the only one here with accesss to a lathe.

I have access to a lathe, however I don't think I would be able machine new threads or chase 48mm threads with something that delicate.

Seems like a poorly machined 48mm might fit

fuglywug wrote: ↑

Sat Sep 25, 2021 2:08 pm

I have access to a lathe, however I don't think I would be able machine new threads or chase 48mm threads with something that delicate.

Seems like a poorly machined 48mm might fit

Assuming one could get the lens out non-destructively, it would probably be easier to machine a replacement mount rather than attempt to line up and chase the threads.

Nick, you might try shaving the crests of a 48mm thread (in your lathe) to fit. With only a 2-3 threads engagement I'd think 32tpi and .75mm could engage at least a couple threads deep. A 48mm UV filter could make a good lens protector and would be cheap to try. The glass is typically easily removed and replaced with a spanner.

Not sure I'd mount a ring light on it as well - but ring lights tend to flatten subjects and LEDs adjustable from the side can often better reveal deails. You might decide you don't need one.

If your lathe takes 5c collets and can cut 32tpi, then "JFK" machinable collets do a superb job of holding and machining fiddly things like lens adapters. https://www.jfkprecisionproducts.com/5- ... llets.html

I tried a generic 1.5x I have a few of (came with some other stuff) and was pleasantly surprised by the image. This was on a 580 with 15x uwf eyepieces, but it threaded on part of a turn, enough to hold, and image quality was fine, no serious complaints, though resolution wasn't amazing at max zoom (kind of always true with the 580 though, since it seems to basically have thr same lenses as a 570 but pushed up a bit to make more space under the oculars for accessories).

I have threadef a 48MM .5X on a 580 and I get about the same but enough to hold. Threading on a couple of more times shifts the thread crests slightly and it goes on a little more. The working distance is extreme and it barely focuses with the microscope mounted on the commonly found stand.

Ok thanks, good to know there is a chance of getting a lens to thread on a bit.

I got a flashlight and sanded the head down with a belt sander until it fit the light mounting hole. I tried to machine a taper on the lathe but gave up due to the difficulty of mounting the flashlight in the chuck. The narrow beam perfectly covers the viewing area and it's plenty bright.

The model I got is the coast HP1. It has some good features for this application:

-Only a bit larger than the mounting hole
-Only $10
-Adjustable beam width
-Only on off - no flashing mode or dim mode
-Power button on the back
-Excellent brightness

And some bad:

-Beam width adjustment is accomplished by sliding the lens longitudinally - not twisting. So when you push the power button with it mounted in the scope the beam defocuses. I fixed this with some epoxy
-not easy to mount in the lathe
-only 2hrs runtime on one AA

Sanding the light down was a bit of a pain, but now that it's done it fits perfectly, and the brightness is excellent. If I had to do it over again I might get a smaller diameter light and use an o-ring as suggested earlier.

One of the problems I have encountered with led spots is the discolouration gradient. I see it in your last picture. A yellow ring around a central bright spot. Often there is an odd coloured central area as well. Yellow. Filtering out the yellow ends up absorbing intensity and there is still the problem of uneven filtering. It just really mutes a light source that is very uneven. What I have found works best is a combination of led and halogen or incandescent, combined with a ringlight. You get a more even daylight type of light and it is tuneable.

I believe the yellow ring you're seeing is just a photographic artifact. Probably something to do with auto white balance and the center being blown out. In person I can't discern any difference in brightness or color temperature within the field of view. The attached image is a better representation of what it looks like in person (including color temperature), with the dots being the edge of the field of view at lowest power.

That being said, if I broaden the beam a very non-uniform gray area opens up in the center. Fortunately the narrowest setting covers the field of view perfectly.

Also, I have to agree with Pete. After using the flashlight and the ring light I find I prefer the flashlight. I just makes for a more pleasing, dramatic image. I also like the fact that I don't need to plug the scope into an outlet to use it.

You might find putting a polarizer over the light and a rotstable polarozer in front of tbe lens gives a pleasing tunability to reflections. It is great on ring lights anyway.

Thanks scarodactyl, I will keep that in mind.

The ‘yellow ring’ … a.k.a. ‘blue centre’ is attributable to the construction details of ‘White’ LEDs

Broadly speaking : A blue-emitting LED is immersed in a yellow-emitting phosphor.

Unless very well diffused; this structure will be evident in an optical projection.
… torches/flashlights do not commonly incorporate diffusers !

MichaelG.

Yes, I understand how white LEDs function and it makes sense that you could have non-uniform color temperature, but that is not what is happening in this case. There is only about a 1% gradient in color temperature in the FOV.

In the image with the yellow ring, the center area inside the ring is blown out. Because the RGB sensor on the camera is saturated, it is impossible for the camera to "know" the color temperature of that center area and it was read differently than the outer ring, which is not saturated.