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Star-forming emission nebula · evidence and sources

Horsehead Nebula

Also known as Barnard 33, B33.

Catalog Physical data basis, the same label the app shows on the selection card.

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Every aspect, with its origin

One record per aspect. The origin says what kind of thing each value is; the source says where it came from; the limit says what it cannot tell you.

ObservedCatalogComputedReconstructedIllustrativeUndocumented
Physical data Catalog

Measured dimensions

Horsehead Nebula (star-forming emission nebula; central source Sigma Orionis, external ionizing star system): measured footprint 2.4 × 2.5 light-years; display depth 0.3 light-years (not measured); outer radius used for arrival 1.7 light-years.

SourceHubble infrared field and registration
Methodmeasured sky-plane structure with constrained display depth
Appearance Reconstructed

Sky-plane structure with a display depth

The illuminated dust structure samples Hubble infrared light. Its shallow depth is illustrative, not measured tomography. Optical dust absorption and infrared emission differ; compare the source observations in the destination card.

SourceHubble optical silhouette and distance
Methodmeasured sky-plane structure with constrained display depth
LimitEmission points and knots are deterministic presentation samples, not individually catalogued gas parcels.
Appearance Reconstructed

Live telescope view: Hubble WFPC2 · optical / near-IR

The cloud becomes a dark silhouette against background emission. Compare its rim with the infrared-lit dust column. Publisher release: 24 April 2001; this is not the observing epoch.

SourceNASA , NOAO, ESA and The Hubble Heritage Team ( STScI / AURA )
MethodPublisher AVM tangent-plane coordinates, resampled to the original destination field; approximate display registration.
LimitThis observation covers approximately 46% of the destination’s rectangular source field. Outside its footprint, the original observation remains visible. Field edges and detector gaps are not physical boundaries. Source palettes are display colors; shallow scene depth is illustrative, not measured tomography.

What is not measured

  • Appearance: a reconstruction from measurements, not a direct observation. Sky-plane structure with a display depth. Emission points and knots are deterministic presentation samples, not individually catalogued gas parcels.
  • Appearance: a reconstruction from measurements, not a direct observation. Live telescope view: Hubble WFPC2 · optical / near-IR. This observation covers approximately 46% of the destination’s rectangular source field. Outside its footprint, the original observation remains visible. Field edges and detector gaps are not physical boundaries. Source palettes are display colors; shallow scene depth is illustrative, not measured tomography.

Not yet documented

  • Identity: no record. Space Time does not claim a source for this aspect.
  • Position: no record. Space Time does not claim a source for this aspect.
  • Orbit: no record. Space Time does not claim a source for this aspect.

Sources cited

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