A clock drive
kept the selected celestial object in the center of the visual field.
Furthermore, an unpublished study spearheaded by neuroscientist Paul Gamlin of the University of Alabama at Birmingham demonstrates that the eyes' blue-sensitive ganglion cells that relay light signals to the biological clock drive
this pupil constriction in rhesus monkeys--and presumably people.
Around 1650, Robert Hooke adapted this joint to a rotating shaft in a clock drive
Besides, the primary mirror needed to be cleaned, and there was no clock drive
An equatorial mount often comes with a clock drive
The gear is part of the clock drive
which keeps the 80-year-old telescope centered on its subject.
The equatorial mount had a weight-driven clock drive
that was precisely regulated by a spinning flyball governor.
Our home-built clock drive
used surplus gears and various spare parts.
Zhang's manuscript on the water-driven clock drive
, Apparatus for Rotating an Armillary Sphere by Clepsydra Water, is now known only from quotations by later scholars, but they confirm that his armillary was designed to track the Seven Luminaries (Sun, Moon, and the five planets visible to the unaided eye), seasonally significant events, and the times of dawn and dusk, and to verify their proper coordination with the calendar.
I started the clock drive
and camera on the northern one 7 minutes before the graze began, then rushed to the southern scope to record it in person there.
Turn off the clock drive
and slowly sweep east or west within a few hours of the meridian.
Also my economy telescope does not have the luxury of an equatorial mount or a clock drive