Lamp for old light microscope

Everything relating to microscopy hardware: Objectives, eyepieces, lamps and more.
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microfungiandmore
Posts: 2
Joined: Sun Mar 29, 2020 7:03 pm

Lamp for old light microscope

#1 Post by microfungiandmore » Wed Apr 01, 2020 8:58 am

Hello forum!

I am a Danish parasitologist who study all kinds of - well - parasitic organisms in my spare time. I the lucky owner of an old August Voigt light microscope (see pictures), but it is currently without a light source or graticule; I'd like to use it for rust fungi primarily, so correct size of individual spores is important.

The eye piece insert is around standard size - 23 mm - so I can buy a graticule without further problems, but how about the light source? Any ideas as how to set this up most easily? If this has been covered in another thread, please supply me with a link - thanks! :)

Best regards,
Simon from Denmark
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BramHuntingNematodes
Posts: 1538
Joined: Tue Jan 21, 2020 1:29 am
Location: Georgia, USA

Re: Lamp for old light microscope

#2 Post by BramHuntingNematodes » Wed Apr 01, 2020 11:57 am

It is a beautiful scope you have there. I have tinkered with making my own lighting for an older scope, and first you would want a planar mirror for under the condenser. Kohler illumination requires a light source, then a lens to collect and roughly collimate the light, a field Iris, and then the microscope condenser's Iris and lens. A nice thing about an adjustable mirror is that any lamp with the necessary parts can be made to work with some fiddling.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

MichaelG.
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Joined: Mon Apr 10, 2017 8:24 am
Location: North Wales

Re: Lamp for old light microscope

#3 Post by MichaelG. » Wed Apr 01, 2020 2:27 pm

Could you please post a photo of what’s below the stage, Simon

I can see that there must be a condenser there ... but no other detail is really visible.

Thanks
MichaelG.
Too many 'projects'

MicroBob
Posts: 3154
Joined: Sun Dec 25, 2016 9:11 am
Location: Northern Germany

Re: Lamp for old light microscope

#4 Post by MicroBob » Wed Apr 01, 2020 3:01 pm

Hi Simon,
a simple illuminator is this one: https://www.ebay.de/itm/Microscope-Bott ... 3751529055
Power will be sufficient for the 40:1 but already a bit weak for a 100:1 oil immersion objective.

These old horseshoe instruments are often easy to improve with a more modern eyepiece, as long as it fits to the objective in use. On this stage of development usually simple non-correcting eyepieces were used for the lower power objectives and correction eyepieces for the 40:1 and above.

Bob

microfungiandmore
Posts: 2
Joined: Sun Mar 29, 2020 7:03 pm

Re: Lamp for old light microscope

#5 Post by microfungiandmore » Tue Apr 07, 2020 8:24 pm

Thanks everyone for the encouraging replies! I have attached a few more pictures of the microscope - from below this time.
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apochronaut
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Joined: Fri May 15, 2015 12:15 am

Re: Lamp for old light microscope

#6 Post by apochronaut » Tue Apr 07, 2020 8:58 pm

Lamps such as this were made to be used with horseshoe base microscopes, when a mirror was not available. The lamp could be used with a mirror, in it's vertical position or placed inside the horseshoe in the horizontal position with the filtered window facing up under the condenser. They are usually 10-15 watts and the ones I have used work o.k. with higher powered oil immersion objectives. There were similar lamps made by most microscope companies.

Recently, I tried out some direct replacement led bulbs that will fit inside the housing . They also work well but the daylight filter needs to be removed from the lamp window, because the image is too far shifted to the blue.

Since you are in Europe, I would be looking for similar lamps made by Graf Apsco, Reichert, Leitz , Zeiss or Jena sold from one of the European ebay sites. The led bulbs, if I recall will work on 110-220v.
https://www.ebay.com/itm/American-Optic ... Swo-5eUEtP

Mike R
Posts: 1
Joined: Wed Apr 15, 2020 3:38 am

Re: Lamp for old light microscope

#7 Post by Mike R » Wed Apr 15, 2020 4:00 am

Here's a simple and cheap solution: get some L.E.D. tea lights. You can place it on your desk directly under your objective. It's battery-operated (two CR2032 batteries) with a claimed run time of 48 hours. I bought a 12-pack from Amazon for about ten bucks, batteries included. Not only that, but they're water resistant! No more worries about how to get illumination when your kid takes your microscope in the bath tub, ha ha. I put a piece of scotch tape over the light as a light diffuser.

Mine fits right in the lamp mounting hole in my Leitz SM.

Here's a link for the ones I bought:

https://www.amazon.com/gp/product/B07H2 ... UTF8&psc=1

MicroBob
Posts: 3154
Joined: Sun Dec 25, 2016 9:11 am
Location: Northern Germany

Re: Lamp for old light microscope

#8 Post by MicroBob » Wed Apr 15, 2020 5:43 am

Hi Mike,
these tea lights give a light source of quite small diameter. The condensers are typically made to be illuminated with a parallel bundel of light rays of ca. 30mm diameter. With a single LED and no diffusor you will probably see an image with a lot of contrast and little resolution because the numerical aperture of the condenser is not fully used.

Bob

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