Clyde Tombaugh discovered Pluto 80 years ago today. Coincidentally, I spent much of last week working on charts to help people locate and observe Pluto in 2010. And just two weeks ago, Kelly Beatty published an article describing new and exciting findings about Pluto. So this planet — or whatever you want to call it — has been on my mind a lot recently.
I've always been perplexed by the people who felt upset when Mike Brown and his team discovered another object both larger and farther from the Sun than Pluto. For people who don't remember, this object was first named 2003 UB313, then Xena (after the Warrior Princess), and finallly and most appropriately, Eris, after the goddess of discord.
Ever since the Kuiper Belt was discovered in the 1990s, it's been apparent that Pluto is a member of this family. And it seemed extremely likely even then that it was only a matter of time until some Kuiper Belt object proved to be bigger than Pluto. But this doesn't detract from Tombaugh's discovery at all — quite the contrary!
It was obvious from the moment its orbit was calculated that Pluto was different from the other big planets. It seemed like a dead end, a footnote. Now we know that on the contrary, Tombaugh's discovery was a beginning, not an ending; he was a half century ahead of his time when he found the first KBO.
As for me, Pluto's luster certainly hasn't been diminished, since it's the only Kuiper Belt object that I'll ever see through the eyepiece of my own telescope — unless I someday acquire a monster Dob that's capable of splitting Charon from Pluto or spotting 16.9-magnitude Makemake, as Steve Aggas has done.
It's been several years since I last looked at Pluto. I guess I'll have to take a look this summer, if only as a quality check on my own charts. Pluto is in a unique position now, poised to enter the Small Sagittarius Star Cloud, which is truly crawling with 14th-magnitude stars of comparable brightness. I have no idea whether that will make Pluto harder or easier to spot.