After the Messier List, the Herschel's are the next most observed deep-sky objects.
Most amateur astronomers know them by their
NGC or IC numbers, but they started out as a list created by British astronomer William Herschel and his sister Caroline.
From 1782 to 1790, the Herschel's conducted systematic surveys of the night sky, in search of "deep sky" objects, and discovered over 2400.
William's son John later added another 1700+ entries to the list.
Eventually, all of the Herschel objects, along with discoveries from other astronomers were combined and published in 1888 as the New General Catalogue (abbreviated NGC).
In addition to his deep-sky surveys, William Herschel also discovered the planet Uranus and two of it's moons - Titania and Oberon, along with Saturn's moons Mimas and Enceladus.
He also discovered over 800 double & multiple stars.
Caroline discovered 8 comets and was honoured by the Royal Astronomical Society.
Herschel classified his list into eight sub-categories:
Class I - Bright Nebulae;
Class II - Faint Nebulae;
Class III - Very Faint Nebulae;
Class IV - Planetary Nebulae;
Class V - Very Large Nebulae;
Class VI - Very Compressed and Rich Clusters of Stars;
Class VII - Compressed Clusters of Small and Large Stars;
Class VIII - Coarsely Scattered Clusters of Stars.
Herschel 400 map
Distribution of Herschel 400 objects, Red = Galaxies, Green = Nebulae, Yellow = Star Clusters
On the left side of the webpage is my personal observation list of the 'Herschel 400', sorted by NGC number.
I have all 400 objects, either video captured or sketched.
The Herschels and their Catalog! PDF
Hope you enjoyed the visit. Come again soon!
Larry McHenry, Pittsburgh, PA. USA