Ptolemaic magnitude scale
E1022097
The Ptolemaic magnitude scale is an ancient astronomical system, originating with Claudius Ptolemy, that ranks stars by their apparent brightness in six broad classes from first (brightest) to sixth (faintest) magnitude.
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
astronomical brightness scale
ⓘ
historical astronomical system ⓘ stellar magnitude scale ⓘ |
| appliesTo | fixed stars ⓘ |
| approximateDate | circa 150 CE ⓘ |
| assumes | stars grouped into discrete brightness classes ⓘ |
| assumesObserver | average human eye under dark skies ⓘ |
| brightestClass | first magnitude ⓘ |
| catalogueAssociated | Ptolemy star catalogue NERFINISHED ⓘ |
| classificationBasis | naked-eye visual impression ⓘ |
| classificationType | visual brightness class ⓘ |
| classRangeLowerBound | 1 ⓘ |
| classRangeUpperBound | 6 ⓘ |
| comparedToModernScale | qualitative rather than quantitative ⓘ |
| dataType | ordinal scale ⓘ |
| developedBy | Claudius Ptolemy NERFINISHED ⓘ |
| documentationLanguage | Ancient Greek ⓘ |
| era | 2nd century ⓘ |
| faintestClass | sixth magnitude ⓘ |
| field |
astrometry
ⓘ
astronomy ⓘ |
| hasMagnitudeClass |
fifth magnitude
GENERATED
ⓘ
first magnitude GENERATED ⓘ fourth magnitude GENERATED ⓘ second magnitude GENERATED ⓘ sixth magnitude GENERATED ⓘ third magnitude GENERATED ⓘ |
| historicalStatus | superseded ⓘ |
| influenced |
Pogson magnitude scale
NERFINISHED
ⓘ
modern logarithmic magnitude scale ⓘ |
| limitingMagnitude | approximately sixth magnitude ⓘ |
| measures |
apparent brightness of stars
ⓘ
apparent magnitude ⓘ |
| namedAfter | Claudius Ptolemy NERFINISHED ⓘ |
| numberOfClasses | 6 ⓘ |
| observationMethod | unaided eye ⓘ |
| orderingPrinciple | smaller magnitude number indicates brighter star ⓘ |
| originatedIn | ancient Greece ⓘ |
| precision | coarse ⓘ |
| relatedConcept |
apparent magnitude
ⓘ
naked-eye limiting magnitude ⓘ visual magnitude ⓘ |
| replacedBy |
Pogson magnitude scale
ⓘ
logarithmic stellar magnitude system ⓘ |
| usedFor |
cataloguing stars
ⓘ
ranking stellar brightness ⓘ |
| usedInWork | Almagest NERFINISHED ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.