Epi-fluorescent Illumination Alignment Slide
To begin alignment of the arc lamp, focus the collector lens (see below pic) to produce a sharply defined image of the bulb. Centering knobs built onto the lamp-house exterior can then be used to translate the focused arc image directly into the center of the illumination circle produced. Some lamp houses have an internal mirror system that directs a more intense illumination into the aperture. Microscopes equipped with this type of lamphouse will produce two arc images (the actual arc and its mirror image). Use the mirror centering and lamp translation knobs to position the real arc and its mirror image (which is usually less intense) side-by-side, and then use the mirror focus knob to adjust the intensities until they are approximately equal (lamphouses lacking the mirror system will also lack the adjustment knobs, so carefully check the manufacturer’s instructions on lamp adjustment). Finally, use the lamp adjustment knobs to overlay the arc and mirror images as closely as possible.