Jupiter’s Fifth Moon


“On the Discovery of the Fifth Moon of Jupiter”

“Then felt I like some watcher of the skies
When a new planet swims into his ken”


“The best thing that we’re put here for’s to see;
The strongest thing that’s given us to see with’s
A telescope. Someone in every town
Seems to me owes it to the town to keep one.
In Cambridge it may as well be me.”
 —Evan R. Frost

Galileo, the most famous astronomer, architect of the first refracting telescopes, and discoverer of the four moons of Jupiter, was bested this past summer by none other than I, Evander L. Price, star-splitter, planet-puncher, and now, moonkiller. On April 16th, 2015, between 7 and 9pm EST, I discovered the fifth moon of Jupiter. Behold!

To be fair to Galileo, the telescope he was using—better to call it a spyglass—wasn’t all that powerful.  It was probably something like f/50.  It could be confused for a piece of PVC pipe, or perhaps a cane.

He had perfected higher magnifications (x8 to x20) that had never before been accomplished.  It was no Star-Splitter, no 12 foot, 10″, 60-year-old, 2,000 pound refractor which could easily be mistaken for Megatron:

The Loomis-Michael telescope, or “Star-splitter” as I’ve nicknamed it, is a wonderful old telescope.  It was constructed before man set foot on the moon and is almost entirely manual except for a fantastically complex azimuth mount that cog-corrects for the earth’s rotation.  To use the telescope, to point it at what you want to see in the sky, you quite literally have to grab one end or the other and drag it so the business end is pointing in the approximate direction of you.  There are long cords dangling from either side of the tube to assist in this task, but nonetheless the telescope can get itself tangled in such an unreachable position that you have to resort the ol’ stick & coat hanger tool to get it down.

The hard part is finding things you can’t see. Finder stars can help, since most celestial objects are invisible to the eye in light polluted Boston skies, but honestly, if I can’t find what I’m looking for, I just resort to zigzagging across the approximate area of my object, like a cosmic beachcomber, or ancient greek boustrophedon. This technique often yields what you least expected, even if it wasn’t what you most desired.

Planets, however, are pretty easy to find (unless you’re looking for Neptune, Uranus, Pluto, or Planet 9).  If you can see your target, you can sight right down the end of the telescope like you would a rifle, and check if you’ve hit with the finder scope.  The star-splitter becomes akin to a cosmic sniper rifle, a blameless weapon in our collective human battle to satisfy our cosmic curiosity about our place among the infinities.  The Star-splitter obliterates single stars and reveals them for what they are, “nothing else than a congeries of innumerable stars” 


A shot I took of the Milky Way, sans Star-Splitter.

From here on out it all gets a bit embarrassing for me.  Galileo first observed the moons of Jupiter on January 7, 1610.  Initially, he named them after his patrons, the Medici.  “The Medici Moons,” if you will.  But later he decided to stick with the tradition of Greek mythological nomenclature.  The four surrounding moons he named after Jupiter’s lovers: Callisto, Io, Ganymede, and Europa.  He observed them assiduously, marking their position night after night.


Interestingly enough, there is a twitter feed that is dedicated to doing just this every day.   My own observation of Jupiter were inspired by the upcoming (October, 2015) conjunction of Jupiter and Venus.  I wanted to get a good photo, and I did pretty good:

Portrait of Father & Daughter

And at that particular time during my April observations, Jupiter was the most interesting thing to look at. And what a sight!


Four moons! Count’em: 1, 2, 3, 4… …5.  Wait, 5? Sure enough:


Since when are there five moons of Jupiter?  At that moment I was flooded with emotion. I had discovered a fifth moon of Jupiter. I pulled out my phone and wikipedia’d Jupiter: yes, yes there are many, many satellites of Jupiter, but only 4 visible moons.  Was I possibly seeing a colossal piece of debris around Jupiter?  Was there something on my eyepiece?

I checked my eyepiece.  Nothing.  All clear.  So I kept on observing for another half hour, taking hundreds of photos, looking for more proof.  One thing to know about Jupiter is it rotates very rapidly—it does a full rotation every 10 hours or so, which means if you watch it for a few hours, you can watch its famous stormy eye circle from one side to the other.  My mystery black-dot-moon was moving at approximately the same velocity, suggesting it was indeed in orbit around Jupiter.

For about 45 minutes on a warm April evening in Cambridge, I could come up with no other explanation for what I was witnessing except for I had found a new moon of Jupiter.  The euphoria of such a discovery is unlike any feeling I’ve ever had before.  It’s a rush.  My brain felt like it was going sixty miles an hour in first gear. It has to be the closest feeling one can have to winning the PowerBall. I felt, very briefly, like an important part of history.

I’d name her Danae.  Siderius Nuncius would need an update.

Afterwards, I walked over to a nearby bar to meet friend Pete Challis, an actual astronomer.

“Nice pics! Looking good! Sure does look like you found a moon.  Do you know what ab transit is?”

Sure Pete, it’s when a smaller body passes in front of a larger body.

“And do you now what an eclipse is?”

Sure Pete, it’s when a body passes between another body and the sun, and casts a shadow.

“So which of those moons do you think is casting its shadow on the surface?”

Danae…or Callisto. Sure enough, we looked it up on Javascript Jupiter and so it was:javascriptjupiter

I learned many lessons that night:

  1. Looking through a telescope flattens a three dimensional space into two dimensions—this can be mighty confusing!
  2. Occam’s razor fails in the face of grandiosity, which leads to
  3. Humility: amateur astronomy is a humble hobby. In the face of all the infinity one can see through a telescope, we amateur astronomers project our thoughts and minds into space and consider the smallness of our being, the rounding error of our existence.

Unless you’re me, because apparently I look through a telescope with an eye to see how great I am. Greater than Galileo!

Lesson learned.

Up next: my plan to discover Planet 9, and my recent sighting of a live supernova of the double star Albireo that turned out to just be me accidentally unfocusing the telescope.





1 reply »

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s