Датчик точной звездной и солнечной ориентации

[DonPMitchell]

Has anyone seen details about the Sun and star sensors on early Russian planetary probes?  Are there diagrams of how they worked?



This photo shows a typical example (Venera-3).  21K is the sensor for constant solar orientation (for solar batteries).  There are five sensors, some with big holes, some with small holes, one with four holes.  All very specialized.  Why five different ones?

25K is the solar/steller sensor for tri-axial orientation and trajectory correction.  I believe there is a sun and a star sensor inside the dome.  It locks on to the Sun and the star Canopus, and then rotates to orient the spacecraft KDU along any vector.  Does it just move slowly, while the orientation system keeps the spacecraft locked on the star?

These were built at NPO Geofizika-Kosmos, yes?  Do they have a museum or a history webpage?