Three things you never knew* about the NASA Infra-Red Telescope Facility (IRTF), in the first 22 seconds of DiscoveryHD's "Super Comet: After the Impact." *You never knew them because, well, they're totally wrong. 1. NASA IRTF is about the 37th largest observatory in the world, by mirror diameter (the most common way of ranking things). It wasn't even the largest when it was first built - the Hale 5-meter at Palomar had been in use for thirty years. Interestingly, the Keck Observatory, next door to NASA IRTF, was the largest in the world from 1992 until August of 2007, and this show was almost certainly produced during that time. Maybe Keck wouldn't let them film. :) 2. When the scene changes, we're no longer on Mauna Kea at all, but at Observatorio del Roque de los Muchachos, on La Palma in the Canaries. The silver dome in the background is probably the Nordic Optical Telescope, and the building in the immediate foreground may be the