Foto de stock - A composite depicting the Perseid meteor shower on the night of Wednesday, August 12, 2015 as shot from southern Alberta, Canada. . . The image takes in a wide swath of the north and eastern sky, including the radiant of the shower in Perseus at left of centre, near the Double Cluster visible as a clump of stars. All the Perseids can be traced back to this point. Also in the image: the summer Milky Way and, at left, a dim aurora in green and magenta that was barely visible to the eye but was picked up by the camera. The Andromeda Galaxy is at centre. The Pleiades is just on the horizon. . . Apart from some haze from forest fire smoke, it was a near perfect night: warm, dry, just a little wind to keep the bugs at bay, and no Moon. A perfect night for a meteor watch. . . This is a layered stack of 35 images recording three dozen meteors (most Perseids but also a couple of sporadics not aimed back to the radiant in Perseus, such as the bright one at far left). . . The 35 images were selected from 200 shot from 11 pm to 2:30 am that night, with most frames not picking up any meteors. This composite is from the 35 taken over the 3. 5 hours that did record a meteor. Each exposure is 1 minute at f/2. 8 with the 15mm full-frame fish-eye, on the Canon 5D MkII at ISO 3200 (a couple of the early shots in the sequence were at ISO 1600 for 2 minutes). . . The camera was tracking the sky on the Sky-Watcher Star Adventurer tracker, so all images of the stars are aligned and registered out of the camera, with the meteors in their proper position relative to the stars and radiant. I masked out a couple of satellite and aircraft trails that were distracting, and took away from the point of illustrating the radiant of the meteor shower. . . The horizon, however, is from one image, taken early in the sequence. Some of the blue in the sky comes from one of the early shots taken in deep twilight but that contained a nice meteor. And I liked the blue it added. . . All stacking and processing with Adobe Camera Raw and Photoshop.