Another famous nebula is Index Catalogue 434, the Horsehead Nebula, near ζ Orionis.

The Eridanus Group is known to have 31 members with nine listed in the New General Catalogue and two listed in the Index Catalogue.

It was first catalogued by John Louis Emil Dreyer in his 1895 version of the Index Catalogue.

It also gives cross-references to many other catalogues, such as the Index Catalogue of Visual Double Stars, which have been linked to the CSI.

The IC designation comes from the Index Catalogue.

Index Catalogue (IC)

The NGC was later expanded with two Index Catalogues, adding a further 5,386 objects.

Index Catalogue of Library of the Surgeon-General's Office, U.S. Army.

Since 1888 he worked assisting Henri Perrotin at the Nice Observatory, and observed 1431 objects published in the Index Catalogue.

It was first reported by Bigourdan in 1891 and included in Dreyer's first Index Catalogue.