This is a capture of a faint appearance of a STEVE arc during the Kp5 aurora display of July31/Aug 1, 2024. This was at 12:17 a.m. MDT, so on Aug 1. A faint arc or ray was visible to the eye, but the camera recorded the pinkish rays at bottom which are likely STEVE arcs below a more diffuse and fainter red arc which is likely a SAR, a Stable Auroral Red arc. The main green auroral arc with blue sunlit tops is to the left in the northeast. At right are bands of green airglow, which were bright enough this night to see with the unaided eye as faint bands across the south, unusual.

So this was a very colourful sky, at least to the camera.

STEVE = Strong Thermal Emission Velocity Enhancement. STEVE is not a nomal aurora but is a horizontally flowing region of hot gas, usually white or pink. It has been known to evolve out of a SAR arc, which may be what is happening here. However, this was the first frame of a time-lapse which showed the arc developing somewhat but never getting bright.

This is looking east toward the rising autumn constellations (at centre), northeast (at left) and southeast (at right).

This is a single 30-second exposure with the 11mm TTArtisan lens at f/2.8 and on the red-sensitive Canon Ra at ISO 3200. Taken from home in southern Alberta.