The two large open star clusters straddling the Serpens-Ophiuchus border and thus called the S-O Double Cluster. They are IC 4756 at left, a very large and scattered group, and NGC 6633 at right, a more concentrated group. Both are best seen with binoculars, and the field of the 200mm telephoto lens used here simulates a binocular field of view. This is a stack of 6 x 2-minute exposures with the 200mm lens at f/2.8 and Canon 6D MkII at ISO 800.
S-O Double Cluster consisting of: IC4756 in Serpens (at left) and NGC6633 in Ophiuchus (right), two good binocular objects. Thru Vixen 108DD astrograph at f/5 with Pentax 67 body and Fujichrome 400F slide film. 540mm focal length with about 7.5° wide field. Exposure about 20 minutes long taken in moonlight from rising waning Moon. Thus the blue sky which has been emphasized rather than neutralized. Taken July 2003 from home.
The summer constellations of Sagittarius and Scorpius skimming low across the south from my latitude of 51° N, above the trees from my backyard site in rural Alberta. Jupiter is the bright object right of centre; Saturn is left of centre. Altair is at upper left. A number of deep-sky objects show up, particularly the Messier nebulas and star clusters, as well as the Scutum Starcloud left of centre, and above it several large binocular open star clusters. The constellation of Ophiuchus is at right of centre occupying most of the frame. Aquila is at far left along the Milky Way. This is a stack of 4 x 1-minute tracked exposures with the Nikon D750 at ISO 1600 and Sigma 24mm lens at f/2.2, plus one of those exposures blended in for the ground to minimize its blurring. Another exposure taken through the Kenko Softon A filter was blended in to add the star glows, though light cloud this night added some glows naturally.
