IC Catalog
5596 objects in the IC catalog
Index Catalogue
Author
John Louis Emil Dreyer (1852-1926)
Year
1895, 1908
Objekter
5386
The Index Catalogue (IC) is an astronomical catalogue compiled by John Louis Emil Dreyer and published in two parts in 1895 and 1908 as supplements to the New General Catalogue. The IC contains 5,386 objects that were discovered after the NGC was published, continuing the systematic cataloging of deep-sky objects.
Data Sources
- OpenNGC Database - Modern digitized version with corrections and updates
- Wikipedia - Index Catalogue - Historical background and detailed information
Objects are numbered IC 1 through IC 5386. The IC was created to supplement the NGC with newly discovered objects and corrections.
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| Navn | Type | RA | Dek | Mag | Stjernebillede | Handlinger |
|---|
Om deep sky-data
Datakilde
Deep sky object data comes from the OpenNGC database by Mattia Verga. Coordinates, magnitudes, and object classifications are sourced from authoritative astronomical catalogs including NGC, IC, Messier, and Caldwell. Source repository: OpenNGC database
Fotometriske systemer
V-band (Visual): Johnson V-filter centreret omkring ~550 nm (gulgrønt), svarende til det menneskelige øjes højeste følsomhed. Dette er det standardiserede astronomiske magnitudesystem.
B-band (Blue): Johnson B-filter centreret omkring ~440 nm (blåt lys). Bruges når V-magnitud ikke er tilgængelig.
Magnitudeskala
Den astronomiske magnitudskala er logaritmisk. Hvert magnitudetrin svarer til et lysstyrkeforhold på ca. 2,512x. Formlen, der relaterer magnitudeforskel til lysstyrkeforhold, er:
\[m_1 - m_2 = -2.5 \times \log_{10}\left(\frac{F_1}{F_2}\right)\]
hvor m er magnitude og F er flux. Lavere magnitude = lysere objekt.
Farveindeks (B-V)
B-V-farveindekset angiver objektets farve og temperatur:
\[B - V = m_B - m_V\]
Typical values: blue objects have negative B-V, white objects are near 0, yellow objects are near 0.6, and red objects are above 1.0. Reference: Farvekonvertering
Magnitudenotation
Hver magnitudværdi er markeret med (V) for V-bånd eller (B) for B-bånd for at angive det anvendte fotometriske system.
Synlighedsguide:
• Grænse for det blotte øje: ~6.0 mag
• Kikkert: ~10.0 mag
• Lille teleskop (4"): ~12.0 mag
• Mellemstort teleskop (8"): ~14.0 mag
Koordinatsystem
Right Ascension (RA): Celestial longitude in hours:minutes:seconds (0h to 24h).
Declination (Dec): Celestial latitude in degrees:arcminutes:arcseconds (-90 to +90 degrees).
Alle koordinater er i J2000.0-epoken (standardreferenceramme for år 2000).