Star cluster and nebulae survey lists and astronomy observation catalogues are essential for finding cool things to look at or photograph. Imagine seeing a neat object in the sky, like a beautiful cluster of stars; how do you tell other people about it and where to find it? One way is to describe its position relative to bright stars and then teach others how to locate the object using your instructions. Another way is to give coordinates for the object in Right Ascension and Declination, like longitude and latitude, but for the sky. Converting the coordinates to a place to look requires a telescope to be lined up and knowing what the right ascension of the meridian is for a given time – quickly looked up but needs some work. The object requires a name, so you might call it Cool Object 1 or CO1 for short, and that’s pretty much how the catalogues of cool stuff in the sky came about. We even made our list of 12 fantastic objects we call the Milky-Way.Kiwi Catalogue (MWK) in our astronomy observation catalogue – more to come, eventually.
Charles Messier
One of the most well-known star cluster and nebulae catalogues is named after the French astronomer Charles Messier (1730 to 1817). Messier was a comet hunter, and while looking for comets, he noted other fuzzy objects, which he didn’t want to confuse as comets in later observations. His observations were done from Paris, so the objects he saw don’t extend beyond 36 degrees South in declination; therefore, they don’t include many of the fantastic Southern Hemisphere objects we are used to. The final version of Messier’s list had 103 objects, and objects 104 to 110 were added in the 20th century after being attributed to Messier. The Messier Catalog is popular amongst amateur astronomers as they are bright objects and relatively easy to find. There are even events, like Messier Marathons, where astronomers try to see all objects in the catalogue in one night.
Patrick Moore
Many of the Messier Catalogue objects are visible in the Southern Hemisphere. Still, it doesn’t take long to encounter many extraordinary objects that would have been worthy of Messier’s observations but were not visible from Paris. Another collection of remarkable objects was compiled more recently by the famous British Astronomer Patrick Moore. Moore used his other name, Caldwell, to develop a list of objects visible in both hemispheres called the Caldwell Catalogue that could be used in addition to Messier’s list. The Caldwell Catalog uses the prefix C, followed by a number from 1 to 109.
The Herschels
One of the giant families of astronomers was the Herschels. First was William and his sister Caroline, followed by William’s son John. Between them, they compiled a final version of 5079 objects in a list submitted to the Royal Society in 1864 in what was known as the General Catalog. The more powerful telescopes available to the Herschels meant they could resolve some of Messier’s Nebulae into star clusters. Other astronomers also used powerful instruments to survey the sky, including Laugier 1853 and D’Arrest 1856. The Herschels also observed from Cape Town, South Africa, to include the Southern Sky in their list.
Dreyer and the New General Catalogue (NGC)
The development of telescopes improved significantly during the 1800s, and the accuracy of William and Caroline’s observation lists needed to be updated. John did this with the catalogue mentioned above. Also, John Dreyer began work on incorporating the work of the Herschels with other survey observations by D’Arrest, Laugier, and the Rosses. Dreyer was born in Denmark and spent time in Ireland with Lord Rosse so he could do his observations with the Leviathan telescope. In 1878 Dreyer published an update to the General Catalogue in Transactions of the Royal Irish Academy (vol: xxvi). By 1886, Dreyer had pulled together many more observations of his own and those of other astronomers and was asked by the Royal Astronomical Society to assemble a new General Catalogue. This became known as the New General Catalogue or NGC and was published in 1888. It was regarded as the most complete list of star clusters and nebulae (at the end of 1887). Many of the objects that astronomers observe have the prefix NGC.
Dreyer and the Index Catalogue (IC)
Things were moving quickly, and soon after Dreyer published his New General Catalogue, an update needed to be issued. This was done in 1895 when Dreyer published the Index Catalogue (IC) of all new observations since the NGC. This new list included 1529 new objects. Not long after that, in 1908, an addition to the IC was published for observations made since 1895; this brought the IC up to 5386 objects.
Many more star cluster and nebulae survey lists and astronomy observation catalogues are in use, but these are the most common ones amateur astronomers will encounter. You can impress your friends using the catalogue number instead of the common name; for example, Jewell Box Cluster is NGC4755, and Omega Centauri is NGC5129. You might be wondering why there is no mention of galaxies. These weren’t figured out until 1924, so up until then, they were known as spiral nebulae. Clear Skies!
