We got the same problem with a custom built heater locally at the chamber
and at the objective. Our problem was solved by changing the regulator
electronics to a better one (faster and more accurate control). I guess that
"thermal expansion/contraction in the microscope stand itself" may give rise
to quite SLOW variations whereas our previous variations in focus were quite
FAST. We had regular variation in seconds (like 10s or so).

At 08.19 1997-02-12 +0100, Beat Ludin wrote:
>The problem is most likely thermal expansion/contraction in the
>microscope stand itself. Remember there is quite a bit of
>non-temeperature-controlled metal between the points where your lens and
>your table are fixed respectively. I solved my problem by building a
>temperature controlled, front-accessible airflow box that keeps the WHOLE
>microscope at a constant temperature.

-----------------------------------------------
 Martin Köhler
 Department of Molecular Medicine
 Rolf Luft Center for Diabetes Research L6B:1
 Karolinska Hospital
 S-171 76  STOCKHOLM
 SWEDEN
         phone    46-8-7295732
                  46-8-7295725
         fax      46-8-7293658
         E-mail   [log in to unmask]
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