Mask Carrier for Scopes Without
Posted: Wed Aug 10, 2016 1:20 am
My American Optical 20 scope is outfitted with a Phase Contrast Condenser. That condenser does not have a slot for masks or filters.
I enjoy experimenting with darkfield, oblique and van Egmond masks so I considered this something that I would need to address.
In order for these masks to work properly they generally need to be positioned as close to the condenser iris as possible, which is the normal placement for a mask slot or filter carrier. Looking over the AO 20, it occured to me that I might be able to fashion some sort of platform that would rest on the base and lift the masks to the proper height.
I have made other microscope accessories from closed cell foam and I turned to it again for this job. I did some measuring and found that the height from the base to the bottom of the condenser is around 7/8". My foam is 1/2" so two layers would be pretty close.
The lamp aperture in the base is 1.25". I cut two 3" circles from the foam, and cut out a 1.25" circle from the center of both. I then made a cut taking about 1/8" of the thickness off of one of the "donuts". Stacked, they are now the correct height to fit under the condenser.
The extra width of the donut creates a rest for the handle of my home made masks and allow me to manipulate and offset them as I might find necessary.
To use, I place the mask on the donut, then place both on the base and slide them into place under the condenser. Watching at the eyepieces makes centering things easy enough. I can then manipulate the entire stack to fine tune centering, or grab the handle of the mask only and move only that to create a desired effect.
The foam will not harm the finish of the scope, and can stay in place if desired as it does not obstruct the light source. The mask can be extracted and replaced with another very easily. The darkfield, oblique and van Egmond effects are just as good as I have been able to create with my other scopes.
If your scope is slightly different in its configuration, you can easily cut foam pieces to fit nearly any situation you may have.
Hope some of you find this useful
Thanks for reading.
Rod
I enjoy experimenting with darkfield, oblique and van Egmond masks so I considered this something that I would need to address.
In order for these masks to work properly they generally need to be positioned as close to the condenser iris as possible, which is the normal placement for a mask slot or filter carrier. Looking over the AO 20, it occured to me that I might be able to fashion some sort of platform that would rest on the base and lift the masks to the proper height.
I have made other microscope accessories from closed cell foam and I turned to it again for this job. I did some measuring and found that the height from the base to the bottom of the condenser is around 7/8". My foam is 1/2" so two layers would be pretty close.
The lamp aperture in the base is 1.25". I cut two 3" circles from the foam, and cut out a 1.25" circle from the center of both. I then made a cut taking about 1/8" of the thickness off of one of the "donuts". Stacked, they are now the correct height to fit under the condenser.
The extra width of the donut creates a rest for the handle of my home made masks and allow me to manipulate and offset them as I might find necessary.
To use, I place the mask on the donut, then place both on the base and slide them into place under the condenser. Watching at the eyepieces makes centering things easy enough. I can then manipulate the entire stack to fine tune centering, or grab the handle of the mask only and move only that to create a desired effect.
The foam will not harm the finish of the scope, and can stay in place if desired as it does not obstruct the light source. The mask can be extracted and replaced with another very easily. The darkfield, oblique and van Egmond effects are just as good as I have been able to create with my other scopes.
If your scope is slightly different in its configuration, you can easily cut foam pieces to fit nearly any situation you may have.
Hope some of you find this useful
Thanks for reading.
Rod