IC Catalog
5596 objects in the IC catalog
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Author
John Louis Emil Dreyer (1852-1926)
Year
1895, 1908
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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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| பெயர் | வகை | RA | Dec | Mag | நட்சத்திர மண்டலம் | Actions |
|---|
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Data Source
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
Photometric Systems
V-band (Visual): Johnson V filter centered at ~550nm (yellow-green), matching peak sensitivity of human eye. This is the standard astronomical magnitude system.
B-band (Blue): Johnson B filter centered at ~440nm (blue light). Used when V magnitude is unavailable.
Magnitude Scale
The astronomical magnitude scale is logarithmic. Each magnitude step represents a brightness ratio of ~2.512x. The formula relating magnitude difference to brightness ratio is:
\[m_1 - m_2 = -2.5 \times \log_{10}\left(\frac{F_1}{F_2}\right)\]
where m is magnitude and F is flux. Lower magnitude = brighter object.
Color Index (B-V)
The B-V color index indicates object color and temperature:
\[B - V = m_B - m_V\]
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: Color Conversion
Magnitude Notation
Each magnitude value is marked with (V) for V-band or (B) for B-band to indicate the photometric system used.
Visibility Guide:
• Naked eye limit: ~6.0 mag
• Binoculars: ~10.0 mag
• Small telescope (4"): ~12.0 mag
• Medium telescope (8"): ~14.0 mag
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Right Ascension (RA): Celestial longitude in hours:minutes:seconds (0h to 24h).
Declination (Dec): Celestial latitude in degrees:arcminutes:arcseconds (-90 to +90 degrees).
All coordinates are in the J2000.0 epoch (standard reference frame for year 2000).