In 1774, the French astronomer Charles Messier compiled a catalog of 110 celestial objects, primarily in the northern latitudes, as he sought to discern these star clusters and nebulae from the comets he was observing.
More than two centuries later, the British astronomer Sir Patrick Caldwell-Moore (1923-2012) was observing the moon and came across the striking double star cluster known as Perseus Sword Handle. It was not, he noted, in the Messier catalog.
“Why not draw up a catalogue of bright nebular objects omitted by Messier?” Caldwell-Moore wrote in a letter reprinted by the Astronomical League. So he did just that.
His catalog includes bright, deep-sky objects visible in the Southern Hemisphere that are not found in the Messier collection, such as Omega Centauri, Centaurus A, the Jewel Box, and 47 Tucanae, along with dozens of objects in the Northern Hemisphere.
And just as the Messier catalog became a cherished and challenging Astronomical League-sanctioned quest for astronomers and astrophotographers who sought to see or image all 110 objects, this more modern list of 109 objects known as the Caldwell Catalog also became the focus of an observing program at the League. The quest with this catalog has two award categories: seeing or capturing 70 Caldwell objects primarily in the northern latitudes and doing so with the complete list.
Less than a year after he finished successfully photographing all 110 celestial objects included in Messier’s catalog, retired College of Aeronautics professor and current adjunct faculty member William Rankin has completed the 70-object Caldwell Catalog and been recognized with the Astronomical League’s Silver Caldwell Imaging Award.
“Another small achievement on my astrophotography quest,” the modest Rankin said.
Raymond Howard, the League’s Caldwell Programs Coordinator, said in a letter of congratulations to Rankin that the accomplishment helps sustain the passion Caldwell demonstrated with his remarkable catalog.
“Although Sir Patrick is gone, his spirit remains thanks to people like you who carry on his passion,” Howard wrote.
