A Canal, A Telescope, and A Star
What does a canal have to do with the night sky? For me, plenty. I remember visiting the Lachine Canal many times as a child growing up in Montreal. I even have a dim memory of watching the water raise our boat once. But actually standing aboard the Norwegian Dream, a gigantic cruise ship to experience the Panama Canal, had to wait until the fall of 2016. As the water surged quietly into and out of the locks on the Pacific and Caribbean sides of the canal, the ship rose and lowered as gently and as quietly as a toy boat in a bathtub. Being part of it was an amazing experience.
Being in Panama, on both the Pacific and Caribbean sides, led me to recall another childhood memory. When I was in high school I would occasionally bring a tiny telescope I called Alouette. During recess or lunch, I’d bring the telescope out of the school and get a reading on how many sunspots there were on the Sun. The telescope was so small it didn’t capture many sunspots.
I no longer have the original Alouette, but in 1970 I bought a new finderscope. I have now used that telescope, also named Alouette, for 46 years. Made mostly of war surplus materials, the revised Alouette served as a finderscope, but recently it has evolved into a travel telescope. When I first got it, Acadia University physics professor Roy Bishop helped me get it installed and aligned, so I thought it proper that it be given a long-overdue first light ceremony. At his Nova Scotia home on the morning of November 7, we used Alouette to enjoy a traditional view of Jupiter, the object I like to use to begin the careers of most of my telescopes.
What does all this have to do with the Panama Canal? I brought Alouette down there and used it to observe stars not normally visible from my Arizona home. In particular, the “star” of the Panama Canal was Achernar. I’ve seen it from Arizona but only as it lay sleeping at the horizon, opening its eyes and winking at me briefly before setting again. But in Panama, Achernar shone high and prominently in the southern sky.
Because of an effect of the Earth’s wobble called precession, Achernar appears to be moving northward. In a few thousand years it will become more easily visible from most of the United States and even southern Canada.
Achernar is a big star, 6.7 times more massive and 3150 times more luminous than our Sun. Even though it is about 139 light years away, it shines as one of the brightest stars in the sky. It rotates about its axis so quickly that it isn’t even spherical, but instead it is flattened into an oblate spheroid so dramatically that its equator is half again as fat as its poles. Moreover, Achernar is surrounded by a very large gaseous envelope that grows outward from the star, collapses inward and then regrows.
It is this final fact of Achernar’s envelope that brings me back to the Panama Canal. As I looked through Alouette at Achernar, I could imagine that envelope quietly growing and shrinking, just as the waters in the locks, we passed through a few hours earlier rise and fall, lifting and lowering the ships that pass through. The canal helps define two continents. Achernar, even as seen through Alouette, helps define a universe.