Open cluster · Crux
Herschel's Jewel Box
Deep skyC 94NGC 4755
Scientific overview
Herschel's Jewel Box is an open cluster in the constellation Crux. It spans about 7.8 arcminutes of sky.
Location in the sky
Precision measurements
Distances and velocities from SIMBAD · NGC 4755
| Distance | 6,497 ly | SIMBAD · catalogued |
| Physical size (major axis) | 14.741305 ly | SIMBAD · derived |
| Radial velocity | -20 ± 0.7 km/s | SIMBAD · measured |
| Right ascension (ICRS) | 193.415 deg | SIMBAD · measured |
| Declination (ICRS) | -60.371111 deg | SIMBAD · measured |
Full field-level provenance
- Distance: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · mesDistance · dist · 2021A&A...651A.104P · distance indicator: paral · catalogued value · source value 1992 pc · retrieved 2026-07-11
- Physical size (major axis): Centre de données astronomiques de Strasbourg (CDS) · derived (OpenNGC angular size × SIMBAD distance) · physical size = angular size × distance (small-angle); angular size from OpenNGC, distance from SIMBAD mesDistance · derived · retrieved 2026-07-11
- Radial velocity: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · rvz_radvel · 2017A&A...600A.106C · direct catalogue measurement · retrieved 2026-07-11
- Right ascension (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · ra · 2021A&A...647A..19T · direct catalogue measurement · retrieved 2026-07-11
- Declination (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · dec · 2021A&A...647A..19T · direct catalogue measurement · retrieved 2026-07-11
Physical size is derived from the OpenNGC angular size and the catalogued distance (small-angle: size = angle × distance). This is a Galactic object: its Doppler shift is shown as a radial velocity, not a cosmological redshift. Fields a source did not provide are omitted, never invented.
Other objects in Crux
Sources
The primary and reference sources this topic draws on.
- OpenNGCOpenNGC (M. Verga) — NGC/IC, Messier, and Caldwell catalogue data
Openly-licensed deep-sky catalogue: object types, positions, magnitudes, sizes, morphology, and cross-identifiers.