Terence Dickinson (10 November 1943 – 1 February 2023)

A "blink comparison" of asteroid (5272) Dickinson

Seems like just yesterday that we learned of the passing of Terence Dickinson, a prominent figure in amateur astronomy for more than 50 years. Can you believe it's been over a year? Terence Dickinson was an editor of Astronomy magazine in its very first issue back in August of 1973. Indeed, you'll find quite a resume of Terence Dickinson on page 27 in the September 1973 issue of the magazine. All of those accomplishments before his 30th birthday. Wow! It would be more than a decade later, however, when I first saw his name in print, as the author of the popular astronomy book NightWatch. Now in its 4th edition, NightWatch remains one of the most popular introductory books for the fascinating world of backyard astronomy.

My purpose here, however, is neither to review his book nor to offer a biography of Terence Dickinson. You can learn all about those things from Amazon and Wikipedia. No, my subject matter is very narrowly focused on just one sentence from his Wikipedia page, specifically, "In 1994, the International Astronomical Union committee on Minor Planet Nomenclature named asteroid 5272 Dickinson in honour of his 'ability to explain the universe in everyday language.'"

You will find such sentences on the Wikipedia pages of many astronomers, both amateur and professional. "Asteroid [such-and-such] was named in their honor." That's because, unlike comets, the asteroids are named by their discoverers, and they are not allowed to name them after themselves. Some discoverers are so prolific that they never get around to choosing a name for all the asteroids they discovered. It's difficult to come up with, say, 300 names that haven't been used already. Sometimes they get suggestions from friends or others, and sometimes they leave them unnamed, with only the default designation by year (such as the other two asteroids seen in my picture above) that is assigned when the orbit of the asteroid has been fully established through follow-up observations and the asteroid is given an official number. 

It's quite an honor to have a solar system body named after you! And in Terence Dickinson's case, it's not only very well deserved, but also very appropriate. After all, there are asteroids out there with names that honor people, places, and things that have nothing to do with astronomy. For instance, your favorite tennis star, Rafael Nadal has a minor planet named after him (128036 Rafaelnadal), as does your favorite classical music composer (1034 Mozartia). Even the Three Stooges were honored with asteroid names (30439 Moe, 30440 Larry, 30441 Curly, and 30444 Shemp)! That's fine, though. There are more than a million asteroids that need to be given names, so who cares if their namesakes have little to do with astronomy? Even so, it's refreshing to see an astronomer be rewarded with an asteroid name.

The question I wish to put forth here is simply, "What does it mean to have an asteroid named after you?" I mean, you don't get to own the thing. And you're never going to travel there in person, walk around on it, or plant your flag on its surface. As a matter of fact, unless you're an amateur or professional astronomer, you're never going to even see it. Asteroids are physically very small and even the world's largest telescopes cannot magnify them enough to show them as anything other than star-like. The best you can do is go to the JPL Small Body Database, look up the asteroid by name or number, and use the Java app to view its orbit within the solar system.

The famous astronomer Bart Bok probably said it best in satire. When asteroid (1983) Bok was named for him and his wife Priscilla, he thanked the International Astronomical Union for giving him "a little plot of land that I can retire to and live on."

Bart & Priscilla Bok, enjoying their long
retirement together on the land they got
 from the IAU.

Terence Dickinson was, no doubt, happy to have a minor planet named for him. Perhaps he, as an amateur astronomer, had the proper equipment and took the time and effort to track it down and take his own picture of it. I hope so! It wouldn't have been easy, though. He'd have to spend a significant amount of money to purchase the equipment necessary to pull it in. And even then, he'd need to plan and wait for the appropriate time to shoot it (a good use for the JPL orbital viewer app), when it's as close to earth as possible.

For the rest of us, though, there are a number of computer programs that show us where all of these millions of asteroids are each night. The first 100, or so, numbered asteroids can be viewed with backyard telescopes in the 8- to 12-inch range of apertures. When they are closest to earth these asteroids can reach magnitudes brighter than 14.0. But the vast majority of asteroids will require astrophotography because they are too dim to see with backyard telescopes. 

Asteroid (5272) Dickinson, for example, was magnitude 16.3 when I took the above image a few nights ago. I wouldn't be able to see an object that faint by looking through the eyepiece of my 11-inch aperture telescope. And since it looks like a star, the only way I could figure out "which star it is" was to take two images about an hour apart and "blink them" to see which star moved. Turns out (5272) Dickinson wasn't the only asteroid I captured!

I didn't plan on shooting this asteroid. I just happened to see it in my telescope-control star-charting program, near the symbol for one of my target galaxies the other night. Not knowing which "Dickinson" it was named for, I took the time and looked it up. When I saw that it was for Terence, I wanted to take some images and come back to it again in an hour to see its motion and prove to me which object was the asteroid. I find this to be a fun activity. And since I happen to have the equipment to do it, I might as well. Right?

As for me, asteroids are as much as a nuisance as Elon Musk's Starlink satellites. They interfere with my chief interest, which is hunting for supernovae. I try to shoot as many galaxies as I can each night, and I compare the images with my older files, to see if there are any new stars in the galaxies. But the asteroids lie in the plane of the solar system, and so whenever I'm targeting galaxies that are in the zodiac constellations, there is a chance that an asteroid will appear very close to (and even over top of) a galaxy, which could be mistaken as a supernova. Therefore, I need to have the asteroids displayed in my telescope-control software, so that I can know in advance if an asteroid will be superimposed onto one of my target galaxies.   

One of the statistical questions I have to ask while hunting for supernovae, though, is what are the chances when I'm targeting a random galaxy, that an asteroid whose name I recognize will be nearby? Think about this for a second. There are over a million asteroids, a small percentage of which have been named after famous and not-so-famous people. So let's suppose that there are 100,000 asteroids that have been named after people. How many of those names could I possibly know in some meaningful way? For that matter, how many famous people (including astronomers) can I name off the top of my head? I might see, for instance, asteroid (3093) Bergholz or (5402) Kejosmith. I don't know or recognize those names. On the other hand, I know the name of Terence Dickinson, and I would recognize the name if (3252) Johnny were to appear next to one of my targets (yeah, you probably guessed correctly, too, that it's named for Johnny Carson)! But what are the chances that asteroids with familiar names like this would appear next to a galaxy I'm shooting at random on any given night? Hmmm.

Of course, finding a supernova is a very rare thing, too! I try to shoot 10,000 galaxies per year, and when I can succeed in doing that, I'll still only find 5 supernovae, at most, in the same period. So whenever I aim my telescope at a target galaxy and see an asteroid next to it that is named after somebody I'm familiar with, I can't help but marvel over that rare coincidence, too!

In any case, if you are an amateur astronomer and you recognize the name of Terence Dickinson, then join me here in celebrating his lifelong achievements and honors with this picture of his minor planet. 

And tell me, honestly: Where else have you ever seen a picture of (5272) Dickinson?

My copy of NightWatch features a 14-inch
 Celestron SCT on the cover. Later versions
would replace the SCT with a small refractor,
a revolution I will never understand in today's
backyard astronomy. I will always prefer a big
 SCT over a small refractor. Aperture is king.