Question about Tasco 750 Monocular Microscope

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Problems with viewing under low magnification (20x) only red stain

I was looking at cells under low magnification (20X) and noticed that
if I tried to view my stain on these-- dapi, rhodamine; the dapi worked
fine,light seemed to be aligned correctly. However, the red stain did not
show. It appears the light path is blocked -with two circles meeting half
way cancelling each other. This only happens and is the most obvious under
low magnification and with the red stain. If I try to view this with 60X,
I am able to get some of the red, however, you also see a halo - a part of
the field of view with bright light coming through. This is just a recent
development as I had no such problem last week.

So, my question to you, what could be causing this and how can I fix
Any help or advice would be greatly appreciated.

Thank you so much for you time.

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Re: problems with viewing under low magnification (20x)...


Sounds like you are using a Phase Contrast Microscope to me, and if this is the case, you will get just this kind of result, especially if it is not set-up correctly.
Let me have the make and model, and I will happily talk you through this one.

Kind Regards......Dave

Posted on Mar 10, 2008

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Re: problems with viewing under low magnification (20x)...


For the red colour partical your illumination angle should be 0 degree.
As per you exepirience you are getting red at low magnification and not getting at high magnification. at the higer magnification the light deviation you can apriciate more then lower.

try to adjust your light source focusing lenc at higher magnification so at the lower it will be more better,

for the further problem you can contect me any time,



Posted on Feb 20, 2008

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Hi there,

Seing bacteria isn't just about magnification, many
are transparent and need to be stained. Even at X1000, you will see little detail, but can make approximations of shape etc. Here is a good starting point for staining bacteria.
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If I can be of any further help, please don’t hesitate to ask.

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