M13 with 130mm Astro-Physics apo at f/6 with no field flattener (slight camera tilt results in more coma at left of frame), for stack of 6 x 6 minute exposures at ISO 800 with Canon 7D (stock camera, not modified). Auto-guided with SG4. Worked perfectly. Slight rotation around guide star made it impossible for Photoshop to do an auto-align. Had to manually align.
A telephoto lens image of the globular cluster Messier 13 in Hercules. This is shot to simulate the field of view of binoculars for illustration purposes. The star at top is eta Herculis in the Keystone. The pair of red stars ar lower right at Nu1 and Nu2 Corona Borealis. This is a stack of 6 x 1-minute exposures with the 200mm lens at f/2.8 and Canon 6D MkII at ISO 800, tracked but unguided on the Mach 1 mount, on April 28, 2019.
Messier 14, a globular cluster in Ophiuchus. This is a stack of 8 x 4 minute exposures at ISO 1600 with the Canon 7D and 130mm Astro-Physics refractor at f/6 with the 6x7 field flattener. Taken at the SSSP 2012 in Cypress Hills.
