Two things to check out...

1) Does the "warm-table" have any metal parts between the stage and the
specimen. We have seen large changes in focus when heating a piece of
metal if the specimen is sitting on top of the metal. Is there some way to
heat from the top so that the metal is above the specimen instead of under
it.

2) Check out how the ventilation comes into the room. We had a similiar
problem even without heating and it turned out to be caused by cool air
blowing on the table from the HVAC. We jury-rigged a deflector that
prevents the cool air from hitting the table and it fixed our problem.

$0.02 worth

________________________________________________________________________________


Paul Goodwin
Image Analysis Lab
FHCRC, Seattle, WA

On Mon, 10 Feb 1997, emanders wrote:

> THE PROBLEM:
> We study living cells and have some problems with temperature
> controlling. It seems that a variation of less than 0.1 degree C influences the
> focal depth too much. The focal depth changes sometimes 0.5 um.
>
> THE SET-UP:
>   1) 60x/1.4 Nikon (on a Biorad MRC 1000/1024)
>   2) an objective heater and its controller.
>   3) cells on a Glass Bottom Petri dish (MatTek)
>   4) a 'warm table' for the petri-dish and its controller
>
> The heater controllers keep the temperature on 37 C with an accuracy
> of less that 0.1 C so, that seems to be good enough.
>
> THE QUESTION:
>   1) Has anyone similar problems?
>   2) Did anyone solve the problem?
>
>
> Thank for your reply, Erik Manders
>
> CRC Nuclear Structure and Function Group
> Sir William Dunn School of Pathology
> Oxford University
> South Parks Road, Oxford OX1 3RE, UK
> Tel: (+44/0) 1865 275529 (/275500)
> Fax: (+44/0) 1865 275501
> E-Mail: [log in to unmask]
>