Unitron 6mm Widescan eyepiece

Dear All,

I am a new guy in this forum (not new in Astromart though). Let me say hello first.

I got a Unitron 6mm Widescan eyepiece some years ago (something like about $13). It is one of the best wide angle eyepieces I have ever used. It is well worth the money.

I don't know much about Unitron nor this eyepiece. Can anyone give me more information?

Attached Image:

These Widescan eyepieces appear to have been made in
Japan and sold under both the "Unitron" and
"University Optics" brands. More often I see them under
the University brand. They were made in the
late 80s and early 90s.

There was a range of focal lengths
available -- 6, 8, 10, 13, 16, 20, and 25mm in the
1.25" size, and 32mm in the 2" size. Apparent
fields were 80 degrees (70 degrees for the 25mm).

If memory serves, the design is some sort of 5 element
Erfle (grouped as 2-1-2). Perhaps a re-work of the
classic Erfle with modern high index glasses?

The 6mm and 8mm add a Barlow-like negative doublet
lens at the bottom, hence accounting for
their increased physical length.

They are good in long F-ratio scopes, but in fast scopes the
sharpness at the field edge suffers somewhat. Center
sharpness is excellent.

Unitron still exists (www.unitronusa.com), though they
mostly deal in industrial microscopes now. There is also
Unitron in Italy (www.unitronitalia.it) though their
exact relation to Unitron USA is unknown to me.
Unitron Italia currently markets a newer version of the
Widescan (Widescan III).