If you have ever used a star map or application, you would have seen many many objects listed as "NGC(some number)" . But what does that mean?
NGC is short for New General Catalogue - or, more properly, "The New General Catalogue of Nebulae and Clusters of Stars". It is a catalogue compiled by John Dreyer in 1888 (yes, "new" is relative), and contains about 7800 objects.
You may have also encountered objects listed with an "IC" prefix. These are also part of the New General Catalogue - or more precisely the follow-up supplements called "Index Catalogues" - adding another 5400 objects.
The NGC (and ICs) are sufficienty important that they have been updated, most recently in 2019, and it now contains nearly 14000 objects.
Last night, I imaged one of the IC objects - the Rho Ophiuchi cloud complex, centering on IC4604.
This is an amazing and beautiful nebula complex, but it took some post processing to really bring it to life.
