NeoSplan NIC questions

[cmake]

I got to try a couple of NeoSplan NIC's with my BH-2 BHS, but sadly without any prisms.
The results were a bit unsatisfactory for both reflected and transmitted light. The objectives (10x, 20x and 50x) were very noticably NOT parfocal and the images had a washed out look.
Parfocality should be adjustable but are the prisms required for these NIC versions?

[Scarodactyl]

No, the NIC designation just means they are strain free. Are you using these with the bh2-uma illuminator? They are infinity corrected and need that specific tube lens.

[cmake]

Good. I have bh2-uma and it seems like my adjustments were a bit messed up, at least for reflected light. Transmitted light still seems way worse than with dplans.
I'm having this thing serviced later this week so maybe I'll ask the guy to take a look at these too.

For naked eye the objectives do seem a bit hazy. Maybe it's just dust?

[PeteM]

These objectives were often used in industrial environments, and sometimes fumes or dust will coat some lens surfaces. I've had some examples of NeoSplans and their BF/DF counterparts that just had lower contrast with no clear cause. You can carefully inspect (phase telescope or just observation to a light source) to make sure the front and rear elements are clear and that there is no fungus or dust inside. The coatings on the front elements may also be damaged. Inspect with a magnifier or a reversed eyepiece.

If you do see a defect inside, it's possible to carefully dismantle the whole thing and clean each surface. Take careful notes and photos if you take things apart - there is a dizzying array of lenses and spacers - and get any one of them reversed or in the wrong place and things get worse. You also noted the objectives are not parfocal. If they're out more than a little, you might also check the back stop and see if there are telltale signs of someone being into an objective earlier (shiny spots in the spanner holes). If so, they might have reversed a lens etc.?

Remember, too, that these are no cover objectives. They'll be blurry starting at 20x and higher when used with cover slips and transmitted illumination.

[cmake]

The guy servicing my scopes had a quick look at these. A brief cleaning brightened the 20x a bit, but he couldn't figure out the parfocality issue. Switching between 10x and 20x requires about 5 full turns from the fine focusing nob, but 20x and 50x are somewhat parfocal. Also i cannot get 50x decently in focus, but this may be just a lightning issue. My illuminator's light source is a handheld flashlight until i get the transformer properly hooked up.

There's definitely some dirty layers visible inside when checking then with a stereo microscope, but no clear signs of having been disassembled before. Cleaning them myself seems a daunting task, has the process of opening one of these up been publicly documented somewhere?