Table · dataset · 1997
Photometric Measurements in the UBVr 20 System
Listed in IVOA Registry (Virtual Observatory)
In the UBVr photometric system defined by Sandage and Smith (1963), (U-B)20, (B-V)20, and (V-r)20 color indices are given for stars from ten reference lists, along with a LID coded number, V magnitude, number of observations and reference.
Description
A list of weighted means is included for stars appearing on more than one list. The reference list and an explanation of the coded numbering system are included in separate files.
Introduction: The UBVr system is defined by Sandage and Smith (1963). The then recent availability of photomultipliers with S20 cathodes sensitive to the wavelength range 3000 to 8000 A suggested that the customary tricolor photometric system could be extended to include a red point close to 6700 A. The V-r color index can be employed as a good indicator of effective temperature, thanks to its relatively small blanketing effect, compared to B-V. Sandage and Smith also tried to obtain the U, B and V colors as closely as possible to those of Johnson and Morgan's system.
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In 1960, 64 standard stars of the UBV system (Johnson and Morgan 1953; Johnson and Harris 1954) were measured. Comparison of colors obtained in the natural photometric system ubvr 20 with colors from Johnson, Morgan and Harris give: B-V = 1.100(b-v)20 + 1.023 +/-0.004 +-/0.003 U-B = 1.015(u-b)20 - 1.575 +/-0.003 +/-0.006 (Sandage and Smith 1963) These equations show that the UBVr 20 system is close to the UBV system without being identical.
Means were calculated for stars appearing in multiple references according to the customary manner at CDS, based on the number of measures and the weight of each list. All ten lists were given weight 4.
Links
Where it is published
- Reference page cdsarc.cds.unistra.fr/viz-bin/cat/II/15 ↗
landing page · from IVOA Registry
Catalogue records · 2
- VOResource record dc.g-vo.org/oai.xml?verb=GetRecord&metadataPrefix=ivo_vor&identifier=ivo%3… ↗
metadata API · from IVOA Registry
- Registry record (GAVO) dc.g-vo.org/I/cds.vizier/ii/15 ↗
catalogue entry · from IVOA Registry
Topics
- Stated by source
- Optical
- From keywords
- Astronomy & Astrophysics
- Inferred from text
- Astronomical sciences 70%
Provenance · 1 source records, 9 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| IVOA Registry (Virtual Observatory) | ivo://cds.vizier/ii/15 | 11 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[field].anzsrc:group:5101 | enrichment · IVOA Registry | taxonomy-embedding@1.1.0 | title+keywords+description (70%) |
| concepts[field].local:field:astronomy | mapping · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].ivoa_waveband:optical | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| description | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_description |
| license_text | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| publication_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| title | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_title |
| updated_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 |