Welcome to Universum.luUniversum · The astronomy portal
UNIVERSUMSTEVE CIMOLINO · LES VIEUX LIVRES
Menu
The portal / The sky atlases / IC I & II catalogue
The deep sky · Supplements to the NGC

The IC catalogues.
Two series, one sky.

Galaxies, nebulae and clusters: explore IC I and IC II, find their identifications and plan your discoveries in the planetarium.

5 386Index Catalogue numbers.
5,597 entries including components and historical cross-references.
OpenNGC data · 19 October 2026

IC I · IC 1–1529 (1895) IC II · IC 1530–5386 (1908). Choose a series in the filters.

Preparing the catalogue…

Explore the catalogue
Actions
Loading entries…
Select an entry to display its fact sheet. Table magnitudes are measured in the V band.
ObjectTypeConstellationMag. V
Page 1
Position on the celestial sphere in J2000 coordinates. This diagram is a coordinate reference, not a photograph.

IC PROFILE

One entry, one patch of sky.

Constellation
—
Right ascension · J2000
—
Declination · J2000
—
Magnitude total · bande V
—
Magnitude total · bande B
—
Apparent dimensions
—
Position angle of the major axis
—
Galaxy morphology · source code
—
Common names in OpenNGC
—

Other identifications

Explore the constellation →Learn more with SIMBAD ↗

Total magnitude and dimensions alone cannot predict the visibility of a diffuse object. Surface brightness, sky conditions and the instrument also matter.

Reading the catalogue

Two historical supplements to the NGC.

IC I, IC II: what is the difference?

Published in 1895, IC I covers IC 1 to IC 1529, a total of 1,529 designations. Published in 1908, IC II continues from IC 1530 to IC 5386, a total of 3,857 designations. Together they form the Index Catalogue, supplementing J. L. E. Dreyer’s New General Catalogue.

The 5,386 numbers do not represent that many distinct physical objects: the OpenNGC extract contains 5,597 entries, including components and historical cross-references. The 377 duplicates and 9 entries classified as nonexistent are retained and identified.

Coordinates, magnitudes and visibility

Coordinates are given for epoch J2000. Missing data remains unspecified: seven historical entries have no coordinates in the source. No artificial position is created for them.

B and V magnitudes are separate. The filter uses V only; missing values are excluded when a maximum is selected. The total magnitude of a nebula or galaxy does not guarantee visibility: sky conditions, surface brightness and equipment also matter.

From the catalogue to the planetarium

The profile button centres the planetarium on the entry’s coordinates. Planetarium search recognises IC and NGC designations, including their components. Duplicates and entries classified as nonexistent are not added as independent targets.

IC and NGC cross-references open the corresponding profile. Common names and scientific notes remain in the source language. Profiles use existing Messier images where a match exists; other entries show a position diagram.

Sources, licence and data

OpenNGC, Mattia Verga, licence CC BY-SA 4.0. Same snapshot as the NGC catalogue: 19 October 2026, commit be3cd6c54988. Field guide.

OpenNGC combines NED (NASA/IPAC, JPL/Caltech), SIMBAD (CDS, Strasbourg), HyperLEDA, Harold Corwin’s notes and HEASARC tables, among other sources. Field-level sources are recorded in the complete NGC/IC source table.

Universum adaptation: selection of IC entries and displayed fields, preservation of coordinate precision, grouping the regions of Serpens, translation of types and classification by historical series. Adapted data remains under CC BY-SA 4.0. Download IC data · Compressed JSON. CSV exports preserve attribution and licensing.

Original publication references and numbering ranges · CDS/VizieR, document hosted by CRAL. Also browse the NGC catalogue →