One of those 4" APO aerial camera lenses ("triplet") I got from Morningstar Optics (who called it an APO). With black plastic sewer pipe, built a refractor as pictured. Too much lense for my poor Russell eyepiece (sold). Also, I had problems with this photographic lens for visual use and contacted Philip Hopkins at Morningstar who replied:
"You might try using a comacorr or field
flattener/corrector, with that 36mm swa (Russell);
could do wonders..."
I never did....
Only lens and "tube" as shown in lower right photo is being sold. No focuser, diagonal or ep included. Mizar mount also listed on AM.
$50 including shipping CONUS (heavy) Paypal preferred.