Description

This image is a 21-panel mosaic and each position in the sky is an average of several

images (called a stack). The mosaic/stack is made from 584 images, 250 if which were used to make the mosaic plus others that were used for meteors. Each meteor is at the position among the stars at the time of the exposure where the meteor was recorded, thus placed into the mosaic at that same position. The images were obtained between 12:52 and 4:12 AM Mountain Daylight Time, so 3.3 hours of imaging time per camera. Imaging was done with 3 cameras. Canon 6D 20-megapixel digital camera, Sigma 35 mm f/1.4 DG HSM lens at f/1.4. The sky is made up of 246 exposures at ISO 1600 were made, each 30 seconds. Exposure of the stars were tracked using an iOptron SkyTracker. Exposures on the land (4 images) were made with the same camera and lens but with 150 second exposures, ISO 1600, f/1.4, and no tracking. Meteors were also recorded with a Sigma 24 mm f/1.4 lens at f/1.4 on a Canon 1D Mark IV digital camera (30 second exposures at ISO 1600) and a Sigma 15 mm f/2.8 lens on a Canon 7D (2 minute exposures at ISO 1600). These two cameras were on an equatorial platform to track the stars. Images from these cameras were scaled to match the star field in images from the 35 f/1.4 lens on the Canon 6D, and the meteors put into the mosaic at the same position against the stars.

More details and full resolution crops at:

http://www.clarkvision.com/galleries/gallery.astrophoto-1/web/perseid-meteor-shower2015_21-panelmosaic-t2b.j-c1sky.html