Cleaning and Caring for the 40x Objective on your microscope.

The 40x :
Microscope Objective - Troubleshooting Poor Image Quality

 

1. 
   This seems simple, but it happens more often than one would imagine. Make sure the specimen slide has the cover slip side UP. If you have the specimen facing down, the working distance will not be enough to focus THROUGH the glass slide to the specimen UNDERNEATH. The typical working distance of a 40x Objective is 0.65mm on an Achromat objective Your typical class A slide is 1-1.2mm thick. 
2. 
   Make sure you are using the proper  sized cover slip. 0.17mm thick is recommended for optimal specimen viewing.
3. 
   Make sure your condenser is in the correct position. The condenser should be in the uppermost position so that your light is condensed into a point on the focal plane of the specimen.
4. 
   Make Sure your 40x:
   Microscope Objective is clean. You can use a magnifying glass to inspect the front of your 40x lens. You can remove your objective by unscrewing it from the nose piece. Examine the front of the objective under a good light source with your magnifying glass. Never go through the back of the objective, or inside the objective. If the lens appears to be scratched, you should call a
   Microscope technician for  possible repair or replacement. In the event of dirt or oil you will want to gently clean the lens using a cotton Q tip. Use a solution of warm soapy water to dip the cotton Q Tip into, then work the Q tip back and forth between your fingers as it makes contact with the lens. This will  temporarily clean your lens of  dirt. You will want to use air in a can as the second step of the cleaning procedure. You will most likely need to repeat these steps multiple times.  In the event that you have oil on your 40x lens from cross contamination with the 100x Oil objective (which happens frequently) you will need to use petroleum benzene to wipe off immersion oil using a cotton Q tip applicator as before. For optimal results, you should follow up with a cleaning using methyl alcohol using another cotton q tip applicator. Use both Petroleum Benzine and Methyl Alcohol sparingly, as the lens of your objective is held in place with a form of rubberized cement. This cement can fail over time if it is over saturated with cleaning solutions. 

 

If the above steps do not improve the quality of your vision through the 40x, you should call your micrsocope service and repair company. Google Keywork "Microscope Repair"  and narrow it down by the major city near you.