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Oliver,

Are you sure this is *behind* the front lens? have you checked the side 
view in a stereo microscope? I had similar crystals on the outside of a 
comparable objective when somebody did not suck of the PBS after 
imaging. They solved after 15-30 min when I put a Petri dish with 
distilled water under the objective and dipped it in. But if that were 
your problem I would expect that you should have had at least a little 
improvement with 70% Ethanol. You might want to try anyway. If the 
sealing is broken you should expect the water to leak into the objective 
too, at least over night. Nothing much left to loose in your case, if it 
is the sealing.

Steffen


Am 28.05.2018 um 16:38 schrieb Oliver Biehlmaier:
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> Post images on http://www.imgur.com and include the link in your posting.
> *****
>
> Dear fellow microscopists,
>
> We have very strange dirt / crystals -image on: https://imgur.com/a/PjOnsSC - on a Zeiss dipping objective which we are using on our 2ph-tomography system.
>
> We tried to clean it with Ethanol 70%, Ethanol 100%, Chloroform, Ether/Ethanol 30%/70% with zero improvement of the situation.
> Thus we guess that the dirt is inside the objective, very much likely salt crystals originating from the buffer solution that the objective is dipping in.
> Have you ever seen something like this? Is it possible that the sealing of the objective is broken after approx. 3 years of dipping and as a consequence these crystals could build up on the rear side of the front lens?
>
> All the best,
> Oliver
>
>
>
> Oliver Biehlmaier, PhD | Head of Imaging Core Facility  | Biozentrum, University of Basel | Klingelbergstrasse 50/70 | CH-4056 Basel
> Phone: +41 61 207 20 73 | Email: [log in to unmask]<mailto:[log in to unmask]> | www.biozentrum.unibas.ch/imcf<http://www.biozentrum.unibas.ch/imcf> | www.microscopynetwork.unibas.ch<http://www.microscopynetwork.unibas.ch>
>
-- 
------------------------------------------------------------
Steffen Dietzel, PD Dr. rer. nat
Ludwig-Maximilians-Universität München
Biomedical Center (BMC)
Head of the Core Facility Bioimaging

Großhaderner Straße 9
D-82152 Planegg-Martinsried
Germany

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