Arranged in order of increasing apparent size in this montage, they are shown to the same scale. Each individual image was captured using the same camera, then processed in exactly the same manner and to the same degree, with the same software settings.
In reality, M53 and M92 have roughly the same diameter of 110 lightyears. The apparent size difference is due to M53 being 60,000 lightyears distant, compared to 27,000 lightyears for M92.
M13 is significantly larger at 145 lightyears in diameter, and is closer at 23,000 lightyears. It consists of several hundred thousand stars.
These images are the result of RGB data capture from Horsham, using a cooled ZWO ASI2600MM Pro monochrome camera, through an 8-inch Teleskop-Service Ritchey-Chretien Cassegrain reflector.
M53: 2.5h of data capture over 2 evenings in April 2022
M92: 2h of data capture on one evening in May 2022
M13: 2h of data capture on one evening in May 2022
Location: Horsham, West Sussex
Photographer: Graham Wilcock
