Spectra Sure Sharp with custom flange (I've left the
Nikon Nikkormat adaptor on) for sale, along with a
Lumicon Easy Guider (2 inch).
They don't make Sure Sharps anymore and I used this with a Lumicon
Easy Guider (also being sold) on an FS102.
The Sure Sharp is a ronchi type focuser that is removed from the
flange once focus has been acquired and the camera body substituted.
While not a trivial device to use, it does get the job done
and allows you to get good focus for film astrophotography.
Asking (firm) for $90 for the Sure Sharp and Flange + ($5 S/H),
and $110 for the Easy Guider ($5 S/H). Buy both and I'll pay for
Note that the Easy Guider will need an appropriate adaptor
if not used with an FS102.