Celestial Circles

The sun was particularly active last weekend, promising spectacular aurora with KP values of over 7. Unfortunately, the expected nighttime display failed to materialise. Instead, I swung my camera around and took 10 30-second exposures of the night sky, with the trees of a nearby road.

After combining them in Photoshop this is what you get. Not bad for 300 seconds.

Star trails form circular patterns around the celestial pole due to the Earth’s rotation, and in the Northern Hemisphere, these circles are centred on Polaris, the North Star, which barely moves at all in the sky. I wasn’t sure where Polaris was, but it looks like it’s just off the photo.


Apertureƒ/2.8
CameraILCE-7RM5
Focal length24mm
ISO1600
Shutter speed30s

Star Trails in Utah

Star trails around the North Star, Polaris in Utah, United States.

This is a long exposure shot of 930 seconds shot at f/8. The night was fairly clear but cloud crept in during the long exposure. It was a glorious night. We were up in the mountains and away from most light pollution apart from the huge hotel 200m away to the right but you have to have some comfort, right?

Next time I’m going to try stacking shorter exposures using StarStaX and I have to avoid “bright” foreground objects. This photo was pushed too much and shows too much noise. 🙁

Aperture ƒ/8
Camera Canon EOS 6D
Focal length 17mm
ISO 100
Shutter speed 930s