*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

Dear Jianbo,

Although it is difficult to remotely solve your problem, but here are 
some ideas (based on our experiences with motorized stages).
The first question is whether you really see a drift? Do you stay really 
at one location? Or do you acquire images at several locations and 
return to them? In this case what you see is just the reproducibility 
limitations of your system. Assuming that you see a "real drift": you 
stay at one location and the stage continuously drifts, there are a few 
things I could suggest to check.

1) Check the electrical connections of your stage and also whether all 
settings in your control software are correct.
2) If you have a control joystick - check it (exchange it) - as a defect 
(dying) joystick can easily cause such problems.
3) If you have linear encoders - check whether they are still clean. 
Dirty encoders can also lead to strange effects
4) a drift a 500 nm/hours is certainly not negligible but there are 
software tools to get rid of such movements (even without the use of any 
special markers).

Cheers    Gabor

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Hello everyone
> We have an encoded (motorized) stage that drifts around 0.5 um (500nm) per hour to mostly but not always one direction. Putting an enclosed box to surround the microscope seems did not help. Is this something unavoidable for a motorized stage? Is using fiducial marker the only solution if experiment requires high accuracy of XY position over long period of time? I would appreciate for any thought and advice.
>
> Jianbo Chen
> HIV Drug Resistance Program
> National Cancer Institute-Frederick
> Frederick MD 21702
>
> [log in to unmask]
> 301-846-1841
>
> https://ccrod.cancer.gov/confluence/display/CCRSSSCArchive/Home


-- 
Gabor Csucs
Light Microscopy Centre, ETH Zurich
Schafmattstrasse 18, HPM G41
CH-8093, Zurich, Switzerland

Web: www.lmc.ethz.ch
Phone: +41 44 633 6221
Mobile: +41 79 758 21 58
e-mail: [log in to unmask]