Dew shield locking compression ring for William Optics RedCat 51

Dew shield locking compression ring for William Optics RedCat 51 - by Deep Sky Dad

The RedCat51 helical focuser is locked by dew shield tensioning. This means dew shield can rotate freely when helical focuser is unlocked, causing problems for dew shield mounted accessories. This simple compression ring locks the dew shield against the OTA body and prevents it from freely rotating. 

See an explanation video here