Why is locating an object more difficult if you start with the high-power objective rather than the low power obejctive exspically the brightness whats up with that?

Answer 1

The reason it is more difficult is that the 'field of view' is much smaller, the higher the objective power. In other words, you don't have to be so exactly 'on target' with a lower objective power, as the field of view is larger in proportion to the object being viewed, so the object can be farther off to one side or the other, and still be seen. Once found in the lower power field, center the object in the field and then switch to the higher power- the object should then be in the higher power field of view. This is true for microscopes and telescopes, as well as any instrument that magnifies at different powers of magnification.