BH2 and Optiphot rotating stages

[Timor]

I believe both the BH2 and Optiphot allow some degree of rotation of the stage.
Does anyone know if this rotation is around the optical axis, as in a petrological microscope, or is it just for convenience of viewing?
My intended use would be a rough and ready check for pleochromism, and maybe to vary the direction of oblique illumination.
Thanks,
Tim

[PeteM]

It is partial rotation and only roughly (say, .025" or so?) centered. They also won't necessarily hold center location when rotated. Might be good enough for your purpose?? It is useful for things like altering the perceived contrast of DIC or oblique -- or reframing a slide within the limits of rotation.

A proper stage will have bearing surfaces and be centerable. It will hold that center location as its rotated due to the precision bearing surfaces.

[Timor]

Thanks for the answer Pete.
Yes, maybe good enough for my purpose. Only way to know for sure is to try one I suppose. Even if imperfect, at least it would give me another option.
Cheers,
Tim

[viktor j nilsson]

From:
http://www.alanwood.net/downloads/olymp ... ochure.pdf

BH2SVR
A 270°rotation capability makes this stage highly suitable for photographic framing and for differential interference contrast purposes.
Note: Range of rotation is reduced to 65' when a Differential interference contrast condenser is attached.

It's very nice to have a rotating stage with centering mechanism, but you'll be able to get the exact same photographs with a fixed rotating stage.

[Timor]

Pete - Just re-read your reply (0.025 and not 0.25 as I thought) and, trying to visualize the mechanism, I think probably it is just what I was hoping for. For me, neither the pleochroism checking or other purposes need great accuracy. Used with care, so as to not completely 'lose' the item of interest, this would probably be sufficient.

Viktor - Just saw your reply. Thanks for the link - I had searched for an explanation of the use of the stage but I hadn't found this comment. Although I'm not really thinking of photography the benefits would still apply.
Tim