Kepler's Supernova Remnant (SN 1604 / 3C 358 / SNR G004.5+06.8)
Coordinates, kinematic distance (5.1 kpc / 16,600 ly), SN 1604 history, circumstellar bow-shock knots, and data for Kepler's SNR in Ophiuchus.
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 |
|---|---|---|---|---|---|
| Optical shock-knot integrated magnitude | 16 mag | ± 0.6 mag | Integrated optical [O III]/H-alpha radiative knots (1604 peak was V = −2.5) | model-dependent | SIMBAD Astronomical Database (CDS) |
| Heliocentric distance | 16600 ly | ± 2300 ly | HST/Chandra proper motion + Balmer shock velocity & H I absorption (5.1 ± 0.7 kpc) (J2016.0) | high-confidence | SIMBAD Astronomical Database (CDS) |
| Apparent shell diameter | 3 arcmin | ± 0.2 arcmin | Chandra X-ray and VLA radio blast wave (3.0′ × 3.0′) | definitive | SIMBAD Astronomical Database (CDS) |
J2000 Equatorial Sky Chart & Culmination Altitude
The chart below plots Kepler's Supernova Remnant (SN 1604) at RA 17h 30m 42.00s, Dec -21° 29′ 18.0″ within Ophiuchus, 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
Kepler's Supernova Remnant (SN 1604, 3C 358, V843 Ophiuchi) is the expanding 3-arcminute (~14-light-year) debris shell of the most recent supernova unquestionably observed to explode inside our own Milky Way galaxy. First spotted in northern Italy on October 9, 1604, alongside a grand conjunction of Mars, Jupiter, and Saturn in southern Ophiuchus, the exploding star reached visual magnitude −2.5 (outshining Jupiter and every star in the night sky) and was tracked for a full year by Johannes Kepler—who published his landmark account De Stella Nova in Pede Serpentarii in 1606. Walter Baade recovered the faint optical nebulosity in 1941 using red-sensitive plates on the 100-inch Mount Wilson reflector.
For decades, astronomers were puzzled by a major paradox in Kepler's SNR: Chandra X-ray spectroscopy reveals an immense mass of iron and silicon ejecta with virtually no oxygen and no central neutron star—proving it was a Type Ia thermonuclear white-dwarf explosion—yet the northern rim is slamming into a nitrogen-rich circumstellar bow shock shed by a fast-moving asymptotic giant branch star, and the system sits 1,900 light-years above the Galactic plane.
Modern 'core-degenerate' or symbiotic binary models explain this puzzle: the exploding white dwarf orbited a mass-losing AGB companion star moving at ~250 km/s, so when the white dwarf detonated in 1604, its 5,000-km/s blast wave plowed directly into the dense wind bow shock carved by the binary prior to the explosion.
Practical Visual Observing Guide
- Located in the southern 'foot' of Ophiuchus at RA 17h 30.7m, Dec −21°29′, just 1.6° northwest of 4.4-magnitude Xi Ophiuchi (ξ Oph) and 35′ west of the globular cluster NGC 6355.
- Because of heavy foreground dust extinction (2.8 magnitudes in V) and its 16,600-light-year distance, the optical knots on the western and northern rims shine around magnitude 16–19 and require long-exposure CCD/CMOS imaging or 500 mm+ apertures under pristine skies.
- In 100–250 mm telescopes, observers can frame Kepler's historical 3-arcminute explosion site alongside the 9.5-magnitude globular cluster NGC 6355 just 35′ to the east.
Catalog Cross-Identifications & Aliases
Common Aliases: SN 1604 · Kepler's Supernova Remnant · Kepler's Star · 3C 358 · V843 Ophiuchi
| Catalog Authority | Identifier |
|---|---|
| SIMBAD | SN 1604 |
| WIKIDATA | Q320670 |
Related Objects, Comparisons & Guides
Tycho's Supernova Remnant (SN 1572 / 3C 10)
Coordinates, distance (2.8 kpc / 9,100 ly), SN 1572 Type Ia light-echo spectrum, Chandra X-ray stripes, and data for Tycho's SNR in Cassiopeia.
SN 1006 Remnant (Brightest Recorded Supernova)
Coordinates, Gaia/kinematic distance (2.18 kpc), −7.5 mag historical peak in 1006 CE, Schweizer-Middleditch background star, and SN 1006 data in Lupus.
Crab Nebula (Messier 1 Supernova Remnant)
Coordinates, Gaia DR3 distance (1.96 kpc), SN 1054 history, pulsar wind physics, and observing guide for the Crab Nebula (M1) in Taurus.
Apparent vs Absolute Magnitude Explained
Understand the logarithmic Pogson astronomical magnitude scale, apparent visual magnitude (m), absolute magnitude (M at 10 parsecs), and bolometric corrections.
Measurement Uncertainty & Optics in Astronomy
How random vs systematic errors, asymmetric error bars, model dependencies, and optical aperture/exit-pupil limits shape astronomical measurements.
Scientific Sources & Dataset Provenance
- 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
- 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