to hopefully capture star trails that look circular tonight.

If you view previous star trail photos I've done - such as this one, if you look up and sideways, you will notice that the circle of stars looks all crinkled and deformed.

That's because the camera's stitcher takes liberties with the edges of the fisheye images to stitch them together such that the features in the edges of both half-spheres match up. That's not great, and there isn't much I can do about it 🙁

To avoid this, I 3D-printed an equatorial mount for the camera: it positions the camera so the center of the image of the front lens points directly at the celestial north pole in my neck of the woods (the latitude where I live is baked into the print):

That way, almost all the stars that are visible here will be contained solely within the front image, will spin around the center of the image, and any deformation should occur pretty much only where the horizon meets the plane of the stitch line, as no stars are visible at the back of the camera where our trees and our house block the view.

Unfortunately, it also means that the nadir of the image is now situated just below the horizon instead of being hidden at the bottom of the sphere (because we live rather high up north), and it's quite visible. Here is a flat projection of a photo taken with the camera earlier:

I'm hoping it will disappear - or at least fade away enough to be inconspicuous - in the dark of the night.

The camera is shooting now. It'll take one image of the night sky every 15 seconds during the entire night. We should have totally clear nights tonight and tomorrow night.

Either we don't get any northern lights tonight and I'm hoping the camera will capture a nice, round-looking star trail, or I'm hoping we'll get strong auroral activity and we get spectacular northern lights overhead, where the image is clearest with the camera mounted in this position.

Stay tuned for the results tomorrow 🙂