Twin Cities aviation enthusiasts had a rare treat on Friday, when NASA's airborne telescope landed at Minneapolis-St. Paul International.
Called the Stratospheric Observatory for Infrared Astronomy, or SOFIA, the modified Boeing 747 carries a 106-inch reflecting telescope.
By cruising at altitudes of 38,000-45,000 feet, this puts it above 99 percent of the Earth's infrared-blocking atmosphere, "allowing astronomers to study the solar system and beyond in ways that are not possible with ground-based telescopes."
And of course, because it can land after every journey, its telescope can be recalibrated unlike deep-space telescopes.
It was stopping at the Twin Cities airport to clear customs and refuel after a stay in Germany, with the German Aerospace Center having part-funded the craft.
Landing at around noon, it took off again at 4 p.m., bound for its base in Palmdale, California.
It led to a huge crowd at the MSP Airport viewing area, with the picture above and those below taken by Burnsville-based Jet Tip, which monitors unusual aircraft movements.