When setting up the school's Celestron 130GT telescopes you'll have two choices of finderscope (the smaller, wider optic that rides on top of the main optical tube).

The first choice, which the telescopes come with, is a sort of dotted reticle that I don't think has any magnification. In all honesty, I struggle with this one, because the tint it has means finding stars under sub-optimal sky darkness (such as is the case 80% of the time on campus) is significantly more difficult. Instead, I opt for the second finderscope.

The second choice, which lives in a box of assorted eyepiece accessories, is a 90* tube that rides on a dovetail too narrow to seat into the saddle of the telescopes. A #2 pencil is the perfect size and shape to fill the void left. Simply slide both in side by side, with the pencil on the side of the saddle away from the snug-screw, and tighten the assembly down. This eyepiece is the perfect width for for centering larger objects in greater magnification uses (like the Sun or Moon when using the 10mm eyepiece) or star hopping to find smaller objects.