Match the following:

List I

List II

P. Axis of telescope

1. The apparent movement of the image relative to the cross-chairs is known as Parallax

Q. Axis of Bubble tube

2. Imaginary line tangential to the longitudinal curve of the bubble tube at its middle point.

R. Line of Collimation

3. Imaginary line passing through the intersection of crosshairs at the diaphragm and the optical center of the object-glass and its continuation.

S. Parallax

4. Imaginary line passing through the optical center of the object glass and the optical center of the eye-piece.

Question

List I	List II
P. Axis of telescope	1. The apparent movement of the image relative to the cross-chairs is known as Parallax
Q. Axis of Bubble tube	2. Imaginary line tangential to the longitudinal curve of the bubble tube at its middle point.
R. Line of Collimation	3. Imaginary line passing through the intersection of crosshairs at the diaphragm and the optical center of the object-glass and its continuation.
S. Parallax	4. Imaginary line passing through the optical center of the object glass and the optical center of the eye-piece.