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More pictures here:
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After recent experience with an Ortho Illuminator under an American Optical 10, I found having a 100 watt lamp could be an advantage for photography. I have that system set up as a dedicated darkfield stand, and as I also had an interest in Phase Contrast it set me to thinking about another stand.
I became interested in the AO 20 as a possible solution. It offered some accessory compatibility to the 10, sported some interesting and useful features like the integrated filter system, and of course, had the 100 watt lighting that would be an asset, especially for Phase Contrast.
I had begun to gather the pieces for a phase system over a month or two as deals would pop up on eBay. First up was the 10 and 40x Plan Achro dark phase objectives. Then came the matching 100x.
Kurt had mentioned that he might have a Phase Condenser Turret he would let go, so I took him up on his offer and we struck a deal. He advised that he did not have the 100x annulus, so that was added to the shopping list.
Needing the annulus and the 20x Plan Phase objective. I placed a Wanted Ad on MicrobeHunter and sent a couple of emails as well to people that I knew might be able to help. Charles stepped forward, and was able to supply both for me and so a deal was made.
Special Thanks to both Kurt and Charles for their help.
I had the bits for the phase system, now I needed a stand.
Watching eBay for a AO 20, eventually one turned up. Seemed to be in good shape, trinoc, lampholder and transformer included and in working order. As I was watching the listing and contemplating the purchase, the seller lowered the price 20%, which I took as a sign, and bought it.
Upon arrival all seemed to be as represented. Even before cleaning it up I stepped through the setup procedure for a quick look in brightfield. It became immediately clear something was wrong. There was a very large shadow showing in the 10x field whose presence could be seen to a lesser, but unacceptable degree at higher powers as well. Further inspection showed that the rear condenser was cracked. Not good.
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I advised the seller of the issue, and after a quick discussion we agreed that I would see if I could find the part to fix it, if I could I would advise as to the cost and the seller would decide how they wanted to proceed.
After a wanted ad and some calls did not turn up the part, I started to consider buying a parts stand. I found one in good shape that was missing the lampholder and transformer, I advised the original seller of the cost and we settled on a refund that amounted to about half of the original scope's cost.
I asked the seller of the parts stand to check the rear condenser to assure me that it was not cracked, and finding it was in good shape the deal was made.
A few days later it arrived. While a bit dusty, it was in good shape. I removed the bottom plate to swap out the condensers, and immediately noticed that things were very different. The condenser seemed to be of a different design, the cast metal lamphouse frame was different with a different sheet metal shielding around it. The entire lamphouse was positioned further back by about an inch. This might be a problem.
- First Stand
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- Second Stand
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As I sat and contemplated the issue, I examined the scope a bit further. It really was in good shape. It had a nice graduated stage that also showed less wear than the first scope. It also amazingly had all eight of the filters present in the filter wheels, where as the first scope had none. It seemed to me that the difference in the lamphouse arrangement was likely an advantage as well. It occurred to me that maybe this was the stand to use to build my system.
I installed the lampholder and turned the transformer to the lowest position, 9.5V. The lamp was incredibly bright. I had removed the filters for cleaning and it was clear that I needed to get at least the neutral density filters back in place to be able to use the scope. I cleaned and reinstalled all of the filter and tried again with the 50% ND filter in line - much better.
After a quick look at the manual for a refresher on the Kohler set up procedure for this scope, it was throwing up some very nice views. The stage movements were a bit stiff, but nothing that couldn't be addressed with cleaning and relubing. This was the stand.
After a good and thorough dusting, cleaning up stains, scuffs, adhesive tape residue, and some cleaning and relubing some of the mechanisms, it was looking great and working well.
Installation and calibration of the phase system went without issue. I had picked up the AO Phasestar Aperture Viewing Unit for the scope. Installed under the head, it performs the task of the phase telescope in helping align the phase ring in the objective with the phase annulus in the turret. It is a very nice convenience, and made dialing in the phase system quick and easy.
So while it took a bit more effort and time than I planned, in the end I accomplished what I had set out to do. A really nice 100 watt stand with a great Phase Contrast system. Now to mount up that camera and get to "work".
), the auction ended at $20 plus $16 shipping. Because of the issues that entire amount was refunded. I spent $24 shipped to grab the only listed original replacement eyepiece, and have now spent another $26 shipped on the 2x objective.
