In case you did not watch the debate tonight (and honestly I tuned most of it out), I am honor-bound to tell you about what turned out to be the most entertaining part of it. Senator John McCain, self-proclaimed earmark maverick, accused Barack Obama of being completely immersed in the pork-barrel culture of Washington. Specifically, he noted a $3 million earmark for an “overhead projector” for a planetarium.

I do not know specifically what he was referring to, but I can make a few educated guesses. The planetarium in question was probably the Adler Planetarium in Chicago (a designated historical landmark), and the “overhead projector” was probably their new fulldome digital video system.

Someone who knows more about planetarium science than I should correct any mistakes in what I say, because this is all based on old and unreliable knowledge. But here goes anyway. Planetariums use one of two projection systems, a Zeiss type system or a digital projection (fulldome) system. Zeiss projectors have been around with their same basic design since 1924 and are used almost ubiquitously. Digital projectors started coming on the scene only within the last decade. While Zeiss projectors can show an extremely detailed and accurate view of the night sky, they are limited by their basic design and can also be a pain to use. Digital projectors, which I guess technically are overhead projectors, are infinitely more versatile but are exceedingly expensive. The Adler Planetarium is one of only a handful of planetariums use a digital system. (They actually have one of each.)

$3 million for an overhead projector that can show incredible detail of the night sky from any perspective or time, show clear and sharp digital video, and serve as a sophisticated educational and scientific tool seems like a good investment of taxpayer money to me. In paying my taxes, I’m happy to support this kind of project. Too bad John McCain thinks differently.

By the way, I know it’s “planetaria”. Don’t waste comment space.