Ready References
Essential Technologies for Making Accurate PC-Based Measurements
Variable Stars Explained
Signal Generators and Their Uses
Fields of Gravitation
Geologic Time
Using a Naked-Eye Starmap
Beating the Seeing
Ready References Essential Technologies for Making Accurate PC-Based Measurements Variable Stars Explained Signal Generators and Their Uses Fields of Gravitation Geologic Time 
Using a Naked-Eye Starmap Beating the Seeing