Bright flare in darkfield scope.

ScottH · Post by **ScottH** » Sun Feb 01, 2015 8:40 pm

I recently aquired another Bausch and Lomb Balplan Microscope with a parabaloid condenser for darkfield. When using the scope for darkfield I am getting a bright flare on one side that looks a little like astigmatism. I can not seem to isolate where the flare is coming from. It's not my eyes I had someone else check. I swapped the head with another scope, swapped eyepieces, swapped objectives, rotated the condensor, centered and recentered the filament (100 watt halogen external). Nothing seems to move the direction of the flare. The optics don't appear to be pinched, out of focus airy disks look really good. The only other thing that is different is that the filament doesnt seem quite as sharp when in focus as with my other scopes. THhe scope appears quite original and well maintained and except for some dust quite clean. Any thoughts on running down this flare?

Scott

Pau · Post by **Pau** » Mon Feb 02, 2015 4:54 am

If you take pictures with the scope, please post some samples to take a look if it seems an internal reflection or an optical aberration.
In principle you've done the adequate variations to isolate the problem, maybe just also to put the DF condenser in your other microscope if possible.
Is the lower NA of the condenser significatively higher than the objective NA?

ScottH · Post by **ScottH** » Mon Feb 02, 2015 7:14 pm

I will try to grab a photo, I will swap condeners but I am not sure if the lights will be bright enough to tell and none of my other stands is configured for an external light.

ScottH · Post by **ScottH** » Sat Feb 07, 2015 5:27 pm

My apologies for taking so long to follow up on this. Work consumed all of my time this week. I took everything off of the stand, took the base off, took the illuminator apart. Put it all back together and it seems to have solved the problem. I can't tell you what I changed or fixed but it is working now.

Scott