Finding Pluto...

I’m conflicted about Pluto. Oh, not Pluto the Disney dog. I love that Pluto just like I love (almost) every other Disney character. No, I am talking that pesky little dwarf planet. The former ninth member of Sol's family and I have a rather complicated relationship.

That relationship began when I was a youngster, a proto-amateur astronomer. Like the rest of my generation, I learned all about The Sun’s Family of Nine Worlds early in elementary school to include memorizing the names all of 'em. Kinda tough for the little folk, but required in the space crazy days of the nineteen sixties. Luckily, there was a mnemonic many of us still cherish: My Very Educated Mother Just Showed Us Nine Planets.

When I stopped being a proto-amateur and became a real one, I naturally wanted to see all of The Nine. I only got eight; Uranus and Neptune were more than challenging enough for my little telescope. I wanted to see Clyde Tombaugh’s and Percival Lowell’s world, but I set that aside for “someday.” Not only will it not show a disk and is, therefore, only identifiable by means of comparing the star patterns in an eyepiece to those of a detailed finder chart, it has a somewhat punishing  visual magnitude that usually hovers around 14 (it can vary from about 13.5 to all the way down to 16).

That was way too dim for my 4-inch Palomar Junior and still too dim even when I moved up to a 6-inch home-brew Newtonian. To corral Pluto, you need at least an 8-inch telescope, and as a young teen I couldn’t dream of owning such a huge instrument. Hell, the Edmund Scientific 8-inch Newt was well over 400 dollars with shipping. This in the days when your old man might bring home 200 a week if your family was firmly entrenched in the middle class.

So, Pluto had to wait for well over a decade, till I glommed onto my first Celestron C8 Orange Tube SCT. Actually, it took me quite a while after I got that scope to get around to chasing Pluto. What finally impelled me to do so was the prospect of moving back to Mobile, Alabama. I knew the dark skies of the Ozarks in Arkansas where I was living would make the hunt far easier than the soupy, humid skies of home.

An 8-inch is big enough for Pluto, but you know what? It is just barely big enough. At magnitude 14 and change, which he was at when I went after him, and which he is at now (14.1 to be precise), he’s in range of an 8-inch with clean optics and dark skies. But easy? No. At about 300x I thought I saw a pinprick in the correct position using Sky & Telescope’s yearly finder chart. I even imagined the speck had moved when I came back a week later. Maybe.

Not to be a party pooper, but, frankly, Pluto was probably even a little easier then than now. He was located away from the summer Milky Way where he is positioned at this time. There were fewer “comparison” stars to use when checking for movement, but there were also far fewer field stars to masquerade as that silly little dwarf than there are today with him over in freaking Sagittarius.

Well, every party needs a pooper and that’s why they invited me. Let me take that a step further. If you want Pluto to be reasonably easy, especially under less than perfect skies, you want to look for him with a 16-inch. Which was my takeaway from the 1999 Texas Star Party.

That May, Pluto was actually slightly brighter than he is this month, being at 13.73. Which didn’t sound too bad. I’d have my 12-inch Dob, Old Betsy, and I’d have the pristine skies of Prude Ranch. I put Pluto on my observing list. “Easy-peazy,” I thought. Hah.

When I got the scope pointed at the proper area of Ophiuchus, I began studying the field in the 12mm Nagler, which, in concert with the 2x TeleVue Big Barlow, which was my big buy at the ’99 TSP, delivered 250x, a pretty good Pluto power. I looked in the eyepiece, and I looked back at the very detailed chart I’d printed with Megastar (software). Nothing hopped out at me that might be the last stop on the way to the Kuiper Belt. I looked some more. After about 15-minutes I spied the minutest, most fraking insignificant speck that appeared to be in the correct position. No, magnitude 13.73 theoretically isn’t that dim in a 12-inch under good skies and with medium-high magnification, but it sure looks dim when it’s just a “small” star in a crowded field.

I will say that when I came back a couple of days later to verify Pluto had moved (via the quick field sketch I’d made the first night), it was somewhat easier to find and see him. But easy in a 12 even under the near perfect skies we had that year? N-O. Not for me, and I suspect not for you. Yes, people say they’ve seen him in a 5-inch, but I am dubious. That would take perfect eyesight, pupils dilated to the max, perfectly dark skies, and very steady seeing—any wavering will make the pinprick that is Pluto disappear.

Again, if you want “easy," I’ve got to say a 16-inch is the way to go. Do you really want easy, though? Pluto isn’t much to look at. In fact he isn’t anything to look at. Just a dim point of light. I believe a little bit of a challenge is called for to make finding Pluto a fun endeavor. If your skies are not perfect, hunt him with a 12 or a 10-inch. If your skies are (near) perfect, and especially if you’ve got considerable observing experience under your belt, haul out an 8-inch.

What with the New Horizons spacecraft approaching Clyde’s Rock, the hunt will be especially fun this July and might be a way for energizing your club during the summer doldrums. Taking a cue from SkyTools author Greg Crinklaw, who suggested to the SkyTools Yahoogroup that chasing Pluto would be an interesting endeavor with NASA’s probe only weeks away, I’ve challenged everybody in my club who owns a 10-inch or larger telescope to try for the dwarf planet from our dark site.

When the spacecraft reveals the weird and wonderful (as it no doubt will) when it comes closest to Pluto and his satellites on July 14^th, it will be extra special for those of us who are in the very tiny minority of humans who’ve laid eyes on the world with their own eyes. No, he’s not very far away when compared to the distant galaxies many of us observe, but he is small and is out there on the edge of the Solar System and it is an undeniable thrill to say you have tracked him down.

What will I use for my Pluto quest? I’m going for the gold, y’all. I will initially attempt the observation with my 10-inch Dobsonian (Zelda). Since I’ve seen Pluto before and know what to expect, I think I can do it if the skies cooperate. The main impediment, I believe—assuming we get some relief from near-constant clouds and rain—will be the terrific haze. If I miss, I’ll kick it up to my 12-inch (Old Betsy). If still no PL do I see, I will get a buddy with a larger scope to put Pluto in the field. Ain’t too proud to beg. Seeing Pluto in concert with New Horizons' arrival is a once in a lifetime opportunity.

Any tips I can give novice Plutophiles running down the rascal  for the first time? Other than "pour on the aperture," use plenty of magnification. Especially if your skies ain’t perfect. 200x to 300x is a good power once you have (you think) Pluto centered. And don’t be hasty. Don’t just take a 2-minute look in the eyepiece and decide “noseeum.” Spend a half hour minimum before throwing in the crying towel.

How can you be sure you have seen Pluto? The time-honored method was to draw the field and come back in a few days as I did at TSP. Even then, however, that really wasn’t necessary any longer. A highly detailed chart for your date, time, and location produced with a computer, showing stars down to the limit of your scope, will probably allow you to pick out Pluto without doubt. In those days I used Megastar. Today it is SkyTools 3 or a new favorite, a freeware planetarium, C2A.

Don’t have nuttin’ but an 8-inch or smaller scope? If you have a camera of some kind, a DSLR or a CCD or a deep space video camera, imaging Pluto is like shooting fish in a barrel if your goto is accurate enough to put the dwarf in the frame of your sensor. If I fail visually, I might break out the Mallincam Xtreme and the Edge 800 (Mrs. Emma Peel). For a rig that can bring back 17^th magnitude galaxies, Pluto ain’t nothin’ (not a thing).

What else is there to say about Pluto? There is that elephant in the living room. He is the world who got demoted. Who the IAU reduced in status from major planet to dwarf. A lot of folks got upset about that. Not just amateur astronomers, who tend to become emotionally invested in such things, but even the general public. Some couldn’t find enough bad words to aim at Neil Tyson, who came out strongly in favor of ending The Nine some years ago.

Why all the  hubbub, Bub? I often wondered about that. So I decided to find out. Who better to ask than the students in my university astronomy labs? PH101 is to some extent a “service course,” drawing students from majors ranging from math and physics to art and P.E. and that seemed the perfect group to ask. I don’t know a thing about doing surveys, so I just asked the kids a few (written) questions. "Have you heard the International Astronomical Union no longer classifies Pluto as a (major) planet? Do you agree with that decision? Why or why not?"

Reading the answers my students gave made one thing clear:  even among the most scientifically literate, science had little to do with Pluto. It was all about emotion. When I boiled it all down, there were two reasons students felt sad for the hellish little world. First, like me, they had fond memories of learning The Nine in elementary school. Secondly, they seemed to at least subconsciously conflate this lonely little world with Disney’s friendly cartoon dog. That last seems strange, but I tend to do it too. When someone says “Pluto,” the first image that pops into my mind is not some godforsaken rock, but Mickey’s faithful hound.

What do I think? As an astronomy educator at a university, I straddle the worlds of professional and amateur astronomy, but I have to come down with most professionals on this one. Considering Pluto the same sort of world as the major planets is just silly. To begin with, he is tiny, 1471 miles in diameter, which is smaller than Earth’s Moon. Why was he ever considered a major planet? Initially, it was thought Pluto was somewhat larger than Earth. Maybe as much as twice the size of our home world. Over the years, he’s been continuously downsized. Every time we’ve learned more about Pluto, he’s gotten smaller.

Secondly, Pluto’s orbit is fairly highly inclined to the ecliptic. He is well out of the plane shared, more or less, by the eight big guys. What does his orbit (which crosses Neptune’s path) look like? It looks like the orbit of a comet or asteroid.

Then there’s the company he keeps. If there were only one world like Pluto out at the edge, I suppose a better case could be for keeping him in the family, but that is not the way it is. There are plenty more where he came from like Sedna (who may be slightly larger than Pluto). Eris and Makemake are pretty clearly bigger than poor PL. There are no doubt thousands of Kuiper Belt Objects, including some that are indeed larger than Pluto. Should the kids have to memorize The Nine Hundred?

What is there in Pluto’s favor? Several cases for retaining him have been made. For example, Pluto has moons. Just like a major planet. But some asteroids have Moons, too. Frankly, most pro-Pluto arguments are, just like my students’ responses, based on emotion. The ground truth is that Pluto is just different from the Sun’s eight major planets.

Frankly, I’m weary of the Pluto dust-up. I’d be OK with it if the IAU decided to grandfather him back into major-planet-hood. But even if they don’t, who cares? If you want Pluto to be a planet, he’s a planet. Who cares what a (poorly attended) IAU session came up with? Frankly, they fumbled the ball so badly on Pluto, especially PR-wise, that I wouldn’t be surprised if they revisit the issue someday.

Anyhow, whatever you think (outraged comments from Pluto's supporters will not sway my opinion, by the way), get out and enjoy Pluto this month, whatever he is. Even if you don’t spot him in your very own telescope, the search will be fun. If you do make out that desolate little pinprick, why all the sweeter...