Spaghetti Nebula (Simeis 147 / Sharpless 2-240)
Coordinates, pulsar VLBI distance (1.30 kpc), 3-degree filamentary shell, runaway pulsar PSR J0538+2817, and guide for Simeis 147 in Taurus.
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) | 10.5 mag | ± 0.8 mag | Wide-field integrated optical filament emission over 3° × 3° | model-dependent | SIMBAD Astronomical Database (CDS) |
| Heliocentric distance | 4240 ly | ± 390 ly | VLBI parallax of PSR J0538+2817 + Gaia DR3 3D dust jump (1.30 ± 0.12 kpc) (J2016.0) | definitive | ESA Gaia Archive — Data Release 3 |
| Apparent shell diameter | 180 arcmin | ± 10 arcmin | Optical H-alpha and radio continuum boundary (180′ × 180′ / 3.0°) | definitive | SIMBAD Astronomical Database (CDS) |
J2000 Equatorial Sky Chart & Culmination Altitude
The chart below plots Spaghetti Nebula (Simeis 147 in Taurus) at RA 05h 40m 00.00s, Dec +27° 50′ 00.0″ within Taurus, 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 Spaghetti Nebula (Simeis 147, Sharpless 2-240, SNR G180.0−01.7) is an enormous, gossamer-thin supernova remnant spanning 3 full degrees across the sky—six times the apparent diameter of the full Moon, or ~220 light-years physically—straddling the border of Taurus and Auriga directly toward the Galactic anticenter. Discovered in 1952 at the Crimean Astrophysical Observatory in Simeiz by Grigory Shajn and Vera Gaze using a fast 25-inch f/1.4 Maksutov camera with narrowband H-alpha filters, Simeis 147 is famed among astrophotographers for its tangled, hair-fine ribbons of shocked hydrogen and oxygen.
Within the western interior of the shell sits the radio and X-ray pulsar PSR J0538+2817 (spinning every 143.16 milliseconds), accompanied by a runaway B0.5 Vn star (HD 37424) that was unbound from a massive pre-supernova binary system when its companion exploded. High-precision VLBA radio astrometry shows that PSR J0538+2817 is racing away from the exact geometric center of Simeis 147 at ~385 km/s, pinning the explosion to ~35,000–40,000 years ago.
Because the blast wave has slowed down to ~80–120 km/s over forty millennia, the hot X-ray interior has largely cooled and recombined into hundreds of radiative optical shock filaments that trace compressed magnetic field lines across the interstellar medium.
Practical Visual Observing Guide
- Centered exactly midway along the 5.5° line connecting Elnath (β Tauri, magnitude 1.65) in the north and Zeta Tauri (ζ Tau, magnitude 3.0, near M1) in the south.
- Simeis 147 is one of the ultimate visual threshold challenges in amateur astronomy because its light is spread across 9 square degrees (~24+ mag/arcsec² average surface brightness).
- Visual detection of the brightest southern and eastern filaments (specifically the 20′-long southern braid at RA 05h 41.2m, Dec +26°24′ and the [O III]-bright eastern arc) requires Bortle 1–2 skies, a 250–400 mm+ rich-field telescope or image-intensified/O-III-filtered wide-field eyepiece at 25×–50× with a 6–7 mm exit pupil.
Catalog Cross-Identifications & Aliases
Common Aliases: Simeis 147 · Spaghetti Nebula · Sharpless 2-240 · SNR G180.0-01.7
| Catalog Authority | Identifier |
|---|---|
| SIMBAD | Simeis 147 |
| WIKIDATA | Q1078675 |
Related Objects, Comparisons & Guides
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.
Jellyfish Nebula (IC 443 Supernova Remnant)
Coordinates, Gaia DR3 distance (1.72 kpc), CXOU J061705.3+222127 pulsar wind nebula, and observing guide for IC 443 in Gemini.
Veil Nebula (Cygnus Loop NGC 6960/6992)
Coordinates, Gaia distance (735 pc), O-III filament structure, and visual filter guide for the Veil Nebula supernova remnant in Cygnus.
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.
Bortle Dark-Sky Scale & Sky Brightness Guide
Reference guide to the 9-class Bortle Dark-Sky Scale, zenith Sky Quality Meter (SQM) readings in mag/arcsec², naked-eye limiting magnitude, and light pollution.
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