We spent the day in Flagstaff Arizona. We stumbled into one of the most interesting places we have ever visited, the Lowell Observatory. This probably doesn't ring any chimes with you. The original telescope on the site (at the time a place with a very dark sky) was used by Percival Lowell to train his Clark refracting telescope (24 inch) to examine Mars because he believed there was alien life up there. He was convinced that the canals connected cities.

Lowell was a trained mathematician (Harvard) and amateur astronomer. He was also very wealthy, which helps a lot. He had done calculations on the orbits of Uranus and Neptune and had concluded that aberrations observed had to be due to the presence of another planet farther out there. Lowell died in 1916 before he could formally get a search going for the Planet X, as he called it. In 1930, Clyde Tombaugh, an aspiring amateur astronomer, was willing to take up the task of finding Planet X while the other astronomers at Lowell wouldn't have anything to do with it. So in 1930, using this telescope, good old Clyde set about exposing plates and taking pictures. His work paid off quickly and he found Planet X which was to eventually be named Pluto. This search involved taking photos (one hour exposures) of the same chunk of sky several nights apart and comparing them with a "blink comparator" to see if anything had changed position. Planets and asteroids change position while stars do not.

As you are all aware, Pluto has been demoted to "dwarf planet" status by the IAU. As with any other so-called scientific governing body, they had to figure out a way to demote Pluto so they came up with some criteria for being called a planet. Pluto met the first two objective criteria: orbit the sun and be a sphere. So they decided on a subjective criterion which was "It must have cleared the neighborhood around its orbit," whatever that means. So Pluto got demoted. Definitely a raw deal.

As an interesting sidelight, a small portion of Clyde Tombaugh's ashes were sent aboard the New Horizons spacecraft which completed a fly-by of Pluto just a couple months ago. It seems fitting that the man who discovered it got to go out in space and visit it.