I’ve been planning my solar eclipse trip for next month, working out where I want to view it and a couple of backup locations if my first choice has bad weather. Because I can drive down to southern Illinois (or Indiana or Kentucky) the morning of the eclipse, I don’t have to worry about getting a hotel—and a good thing, because it’s way too late for that.

I’ve played with a few interactive eclipse maps, and for my money the easiest to use is this one from NASA. It’s based on Google Maps, so you can zoom in and switch between map and aerial views using familiar tools. Clicking a spot on the map brings up a nice popup with all the time and directional information you’re likely to need.

Eclipse info popup

There’s a similar interactive map for the 2024 eclipse, which I hope to see, too. I soon realized that there’s a spot at which the central lines of both eclipses—the lines along which the totality lasts the longest—intersect. Weather permitting, you could park yourself at the same spot to be on the central line for both eclipses. I decided to find that spot.

The proper way to do this, I think, would be to dig into the source code for both pages and figure out a way to get both paths on the same map. I took the easy way out, taking screenshots of both maps and combining them on separate layers in Acorn, giving the top layer some transparency to let the bottom layer show through.

Here’s the map of the general area in southern Illinois.

Two eclipse paths 1

You can see why Carbondale is touting itself as Eclipse Central, but let’s zoom in a little closer.

Two eclipse paths 2

Looks like the intersection is on the shore of Cedar Lake in the Shawnee National Forest, which stretches across a big chunk of southern Illinois. Let’s move in a little closer and switch to an aerial view.

Two eclipse paths 3

And maybe a little closer.

Two eclipse paths 4

So the actual intersection point won’t be very good for viewing unless you’re willing to climb a tree. But sitting in boat offshore would work out nicely.