Greetings from Denmark and request for help (Bertrand lens)

[Valemk]

Hi everyone
My name is Valeria and I’m a geochemistry master student. I recently bought myself a leitz orthoplan, so I can continue my project also at home I really like this microscope, but so far I only have a problem: I need to check the conoscopic interfence pattern of the minerals, but with this microscope I cannot figure out how to do it..
So, the million dollars question is: how can I check if this microscope has a Bertrand lens? And in case it has it already, how/where do I switch it?

Serie nr 895242

Thanks a lot in advance

[MicroBob]

Hi Valeria,

this seems to depend on the tube head you have:

http://www.microscopy-uk.org.uk/mag/art ... oplan.html

Here is a repair manual for the actuator of the Bertrand lens - they seem to be a weak point:

http://www.leitz-ortholux.de/forum/Bert ... Repair.pdf


I don't have an Ortoplan and help much.


Bob

[gastrotrichman]

I think the Leitz Variotube (mentioned and shown in MicroBob's first attachment) can be added to your Orthoplan between the stand and the head. The Variotube has a Bertrand lens. The Variotube Bertrand lens has the same Achilles heel as the Bertrand lens in the Pol head (shown in MicroBob's second attachment): the wire is frequently broken. A Variotube was recently offered on eBay, but it was pretty expensive and the ad did not reveal whether the Bertrand lens was operable.

I know nothing about mineralogy, but I wonder if a phase telescope would work for your purposes. Not as convenient as a Bertrand lens, but, if it would work, possibly a stop-gap solution until you can obtain a Pol head or a Variotube.