Ready References
Beginner's Corner, Oct. 1939
Understanding Celestial Coordinates
Caring for Optics
Setting Up and Observing Program
Basics of Motion Control
Vacuum Thermopiles and the Measurement of Radiant Energy
Geologic Time
Ready References 
Beginner's Corner, Oct. 1939 Understanding Celestial Coordinates Caring for Optics 
Setting Up and Observing Program 
Basics of Motion Control Vacuum Thermopiles and the Measurement of Radiant Energy Geologic Time