Cat's Eye Nebula (NGC 6543 / Caldwell 6)
Coordinates, Gaia DR3 distance (1.07 kpc), William Huggins 1864 nebulium spectroscopy, and high-power observing guide for NGC 6543 in Draco.
Provenance-Backed Scientific Measurements
Every measurement below preserves its unit, uncertainty interval, observational method, reference epoch, quality status, and primary catalog source. See Uncertainty & Provenance for how competing measurements are handled.
| Parameter | Value | Uncertainty | Method & Epoch | Quality Status | Source Archive |
|---|---|---|---|---|---|
| Integrated visual magnitude (V) | 8.1 mag | ± 0.1 mag | Integrated CCD aperture photometry | definitive | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
| Heliocentric distance | 3490 ly | ± 95 ly | Gaia DR3 trigonometric parallax of 11.1-mag central star (1.07 ± 0.03 kpc) (J2016.0) | definitive | ESA Gaia Archive — Data Release 3 |
| Bright inner core diameter | 0.4 arcmin | ± 0.05 arcmin | Bright inner bubbles (25″ × 18″; outer halo IC 4677 spans 5.8′) | definitive | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
J2000 Equatorial Sky Chart & Culmination Altitude
The chart below plots Cat's Eye Nebula (NGC 6543 in Draco) at RA 17h 58m 33.42s, Dec +66° 37′ 59.5″ within Draco, alongside peak meridian transit altitudes for 40°N and 30°S observers. Use the RA/Dec Coordinate Converter to compute exact culmination altitude for your latitude.
Astrophysical Context & Structure
The Cat's Eye Nebula (NGC 6543, Caldwell 6) is one of the most structurally intricate planetary nebulae known, situated 3,490 light-years (1.07 ± 0.03 kiloparsecs) away in Draco—almost at the exact North Ecliptic Pole. Discovered by William Herschel on February 15, 1786, NGC 6543 changed the course of astrophysics on August 29, 1864, when English pioneer William Huggins aimed a visual spectroscope at it and saw not the continuous rainbow of unresolved stars, but three isolated bright green and blue emission lines—proving for the first time that true gaseous nebulae exist in deep space.
Hubble Space Telescope images of NGC 6543 reveal an extraordinary hierarchy of nested structures: a 1,000-year-old inner pair of intersecting elliptical bubbles, two point-symmetric fast polar jets and low-ionization FLIER knots ('Fast Low-Ionization Emission Regions'), and eleven concentric spherical dust shells ejected like tree rings every ~1,500 years during the progenitor star's final asymptotic giant branch thermal pulses.
At the center shines a luminous 11.1-magnitude O7 + [WR] central star (~80,000 K) losing mass via a 1,900-km/s stellar wind, surrounded by a giant 5.8-arcminute (~6-light-year) outer filamentary halo whose brightest western knot is cataloged separately as IC 4677.
Practical Visual Observing Guide
- Located midway between Zeta Draconis (Aldhibah) and Delta Draconis (Altais) inside the head/loop of Draco, just 4 arcminutes from the North Ecliptic Pole.
- Because its 8.1-magnitude light is packed into a tiny 25 × 18 arcsecond core, NGC 6543 has scorching surface brightness (~14.2 mag/arcsec²), triggering cone-cell color vision in even 80–150 mm telescopes as a vivid electric turquoise or emerald-green oval.
- In a 200–350 mm telescope under steady seeing at 250×–450× without a filter, the 11.1-magnitude central star pops out clearly inside the S-curved inner rim; add an O-III filter at 100× under dark skies to spot the detached western halo knot IC 4677.
Catalog Cross-Identifications & Aliases
Common Aliases: NGC 6543 · Cat's Eye Nebula · Caldwell 6
| Catalog Authority | Identifier |
|---|---|
| NGC | NGC 6543 |
| SIMBAD | NGC 6543 |
| WIKIDATA | Q15831 |
Related Objects, Comparisons & Guides
Saturn Nebula (NGC 7009 in Aquarius)
Coordinates, Gaia DR3 distance (1.26 kpc), magnitude 8.0, low-ionization ansae jets, and high-power observing guide for NGC 7009 in Aquarius.
Blue Snowball Nebula (NGC 7662 in Andromeda)
Coordinates, Gaia DR3 distance (1.76 kpc), magnitude 8.3, vivid O-III/He-II blue-green excitation, and observing guide for NGC 7662 in Andromeda.
Ring Nebula (Messier 57 in Lyra)
Coordinates, Gaia DR3 central star distance (787 pc), magnitude 8.8, and telescope observing guide for the Ring Nebula (M57) in Lyra.
Surface Brightness & Extended Objects Guide
Why surface brightness (mag/arcsec²) governs nebula and galaxy visibility more than integrated magnitude, and how exit pupil controls eyepiece contrast.
Celestial Coordinates (RA & Dec) Explained
Practical reference to J2000 equatorial coordinates: Right Ascension (RA in hours, minutes, seconds), Declination (Dec in degrees), and sexagesimal conversion.
Scientific Sources & Dataset Provenance
- ESA Gaia Archive — Data Release 3 (DR3 (2022-06-13)): Gaia Collaboration, Vallenari, A., et al. 2023, A&A, 674, A1 (Gaia Data Release 3) — European Space Agency / Gaia DPAC
- Revised New General Catalogue and Index Catalogue (RNGC/IC) (2024/2026 edition): Steinicke, W. 2010, Observing and Cataloguing Nebulae and Star Clusters (Cambridge Univ. Press); Verga, M. OpenNGC (CC-BY-SA 4.0 / data tables) — Wolfgang Steinicke / OpenNGC
- SIMBAD Astronomical Database (CDS) (2026-10 release): Wenger, M., et al. 2000, A&AS, 143, 9 (The SIMBAD astronomical database) — Centre de Données astronomiques de Strasbourg