A composite of the Perseid meteor shower, on the peak night, Aug 11/12, 2016, looking northeast to the radiant point in Perseus left of centre, with the Pleiades and Hyades clusters in Taurus rising. There are 33 meteors here. Note the fairly consistent green to red tint of each meteor streak. A couple of streaks look more white and might be flaring satellites though their trajectory matches where a Perseid should be. The sky is also filled with bands of red and green airglow which in the time-lapse sequence are moving from south to north, right to left here. The airglow was bright enough that it was visible to the unaided eye as grey bands in the sky, especially the “cloud” around the Pleiades. The reddish/orange patches at upper left are the remains of a long-lived “smoke” trail from an expoding meteor earlier in the evening, which I of course missed capturing. This was taken from the Dark Sky Preserve of Grasslands National Park, Saskatchewan, from the trailhead parking lot at the end of the 70 Mile Butte Road. This is a stack of 31 frames containing meteors (two frames had 2 meteors), shot from 1:13 am to 2:08 a.m. CST, so over 55 minutes. So considering the camera would have missed the fainter meteors and is seeing only one section of the sky, 33 meteors over 55 minutes is a great count, translating to perhaps ~ 100 to 150 over the whole sky? This is from latitude 49° N. The camera was not tracking the sky but was on a fixed tripod. I choose one frame with the best visibility of the airglow as the base layer. For every other meteor layer, I used Free Transform to rotate each frame around a point far off frame at upper left, close to where the celestial pole would be and then nudged each frame to bring the stars into close alignment with the base layer, especially near the meteor being layered in. This placed each meteor in its correct position in the sky in relation to the stars, essential for showing the effect of the radiant point accurately. Each layer above the base sky layer is masked to show just the meteor and is blended with Lighten mode. If I had not manually aligned the sky for each frame, the meteors would have ended up positioned where they appeared in relation to the ground but the radiant point would have been smeared — the meteors would have been in the wrong place. Unfortunately, it’s what I see in a lot of composited meteor shower shots. It would have been easier to have had this camera on a tracker so all frames would have been aligned coming out of the camera. But the other camera was on the tracker! The ground is a mean combined stack of 4 frames to smooth noise in the ground. Each frame is 30 seconds at f/2 with the Sigma 20mm lens and Nikon D750 at ISO 5000. The waxing Moon had set by the time this sequence started, leaving the sky dark and the airglow much more visible.
The Pleiades rising behind the rustic cabins and outbuildings of the historic Larson Ranch in Grasslands National Park, Saskatchewan. Aurora shines to the left in the north while green airglow illuminates the sky to the east above the buildings. Grasslands is a Dark Sky Preserve. And the sky is very dark. All illumination here is natural — note the dark clouds seen against the brighter airglow-lit sky. This is a stack of 4 exposures for the ground to smooth noise and one exposure for the sky, all untracked, and 30 seconds at f/2 with the 20mm Sigma lens and Nikon D750 at ISO 3200.
