A. Never allow any of the leveling-screws to become so tight that they cannot be easily turned by hand. When setting the instrument up over a concrete floor make little holes in the concrete for the points of the tripod-legs to set in. Never wipe the lenses with anything having the least sign of dirt or grit upon it. A perfectly clean chamois is always best. See that all screws are firmly clamped before putting the instrument away in the wooden carrying-box. In removing it from the box, pick it up by placing the hands underneath the worm-gear. Never clamp the instrument too tightly to the tripod-head. After the instrument is once leveled avoid jarring or leaning upon it.
Q. In case the azimuth-instrument will not stay level after performing the usual operation of leveling, how do you adjust the levels?
A. Set one level parallel with two opposite leveling-screws, and bring the bubble to the center by turning these two screws either both inward or both outward. Reverse the telescope through 180°. If the bubble is not in the center, this level is out of adjustment. Now correct one half of the error by using the small steel pin on the little adjusting-screws on the levels, and the other half by using the two opposite leveling-screws referred to above. Now turn the telescope 180° again. If it is still out of level, continue the above method of correction until, on reversing the telescope, no change in motion of the bubble can be observed.
Q. Give a rule for finding the least count of a vernier.
A. Divide the value of the smallest division on the limb or main scale by the number of divisions there are on the vernier. The result is equal to the least count on the vernier.
Q. How would you focus the telescope.
A. Focus the eyepiece until the cross-wires appear rough.
Then turn the telescope on some distant object and focus the objective by means of the focusing-knob until the intersection of the cross-wires remains on the same point, when the eye is moved up and down and to right and left.
Q. Set up the azimuth instrument over a given point; level, orient, and focus it.
(This should be practiced frequently.)