A Versatile Slow-Motion Control
C. D. Geilker · Publications of the Astronomical Society of the Pacific · 1964
In an observing program where photoelectric and photographic observations are frequently alternated, variable-speed slow motions offer great advantage.In fact, if the range of speed variation is sufficient, the double-slide plateholder traditionally used in long guided photographic exposures may be dispensed with, and all guiding accomplished by use of the slow motions.If an auxiliary high-speed motion is instantaneously available for rough positioning using the same pushbutton, the convenience in photoelectric observing is greatly increased.Such a system of slow motions, as used at the Dyer Observatory, is shown in block diagram form in Figure 1, and in detail in Figure 2. Speed variation is accomplished by changing the voltage applied to the armature of a Bodine NSH-12R shunt-wound d.c.motor.Booster transformer T-l adds 25 volts to the high side of the power from the line.This