Galaxies from a variety of wellknown catalogs.

Entity["Galaxy",name] or

represents an entity of type "Galaxy".

[prop]

gives the value of a specified property.

[{propi,}]

gives the value of a list of properties.

[prop,{qualivali,}]

gives the value of a specified property modified by qualifier rules quali->vali.

[Dated[prop,date]]

gives the value of a property associated with a particular date specification.

EntityClass["Galaxy",{propispeci,}]

represents a class of entities with values of propi defined by speci.

Sample Entities

Sample Entity Classes

Properties

  • AlphanumericNamealphanumeric name
    AlternateNamesalternate names
    Altitudealtitude
    AltitudeTransitnext transit altitude
    AngularDiameterFromEarthangular diameter
    AngularRadiusFromEarthangular radius
    ApparentAltitudeapparent altitude
    ApparentMagnitudeapparent magnitude
    Azimuthazimuth
    AzimuthRiseazimuth at rise
    AzimuthSetazimuth at set
    BlueBandMagnitudeblue band magnitude
    BooleanRiseabove the horizon
    Classesclasses
    Constellationconstellation
    DailyTimeAboveHorizondaily time above horizon
    Declinationdeclination
    Diameteraverage diameter
    DistanceFromEarthdistance from Earth
    DistanceFromMilkyWaydistance from the Milky Way center
    DistanceFromSundistance from Sun
    EntityClassesentity classes
    GalacticLatitudegalactic latitude
    GalacticLongitudegalactic longitude
    GalaxyTypegalaxy type
    GravitationalConstantMassProductgravitational constant mass product
    GreenwichHourAngleGreenwich hour angle
    HelioCoordinatesheliocentric XYZ coordinates
    HubbleTypeHubble type
    ICNumberIC number
    Imageimage
    LocalHourAnglelocal hour angle
    MajorAxismajor axis
    Massmass
    MaximalAltitudeTimenext maximum altitude time
    MinorAxisminor axis
    Namename
    NGCNumberNGC number
    ObjectTypeobject type
    PGCNumberPGC number
    PositionAngleposition angle
    RadialVelocityradial velocity
    Radiusaverage radius
    Redshiftredshift
    RightAscensionright ascension
    RiseTimenext rise
    SetTimenext set
    Shapeshape
    SiderealHourAnglesidereal hour angle
    SurfaceBrightnesssurface brightness
    TransitTimenext transit time
    VisualBandMagnitudevisual band magnitude

Details

  • "Galaxy" entities include the majority of galaxies from the Revised New General Catalogue and Index Catalogue, including members of the Messier Catalog.
  • "Galaxy" entity classes include groups based on galaxy type, such as spiral galaxies and elliptical galaxies, as well as groups related to catalog membership, such as Messier objects.
  • Some properties are available for the "Galaxy" entity type as a whole and can be given using the form EntityValue["Galaxy",property]. Such properties include:
  • "Properties"the list of available properties
    "PropertyCanonicalNames"the standard names of available properties
    "SampleEntities"a sample list of available entities (typically of length 10)
    "SampleEntityClasses"a sample list of available entity classes (typically of length 10)
    "EntityCount"number of entities available
    "Entities"the list of available entities
    "EntityCanonicalNames"the standard names of available entities
    "EntityClasses"the list of available entity classes
    "EntityClassCanonicalNames"the standard names of available entity classes
    "PropertyClasses"the list of available property classes
    "PropertyClassCanonicalNames"the standard names of available property classes
    "PropertyCount"number of properties available
  • The following annotations can be used in the third argument of EntityValue["Galaxy",property,annotation]:
  • "Source"source information for the property
    "Date"the date associated with the entity-property value (if any)
    "EntityAssociation"an association of entities and entity-property values
    "PropertyAssociation"an association of properties and entity-property values
    "EntityPropertyAssociation"an association in which the specified entities are keys, and values are a nested association of properties and entity-property values
    "PropertyEntityAssociation"an association in which the specified properties are keys, and values are a nested association of entities and entity-property values
    "Dataset"a dataset in which the specified entities are keys, and values are an association of property names and entity-property values
  • The following annotations can be used in the second argument of EntityValue[property,annotation]:
  • "Qualifiers"the list of possible qualifiers for the property
    "QualifierValues"the list of possible values that can be given to each qualifier
    "DefaultQualifierValues"the list of default values for the property's qualifiers
    "Description"a brief textual description of the property
    "Definition"a detailed textual definition of the property
    "PhysicalQuantity"the physical quantity associated with the entity-property value
    "Unit"the unit associated with the entity-property value
  • A qualifier value of Automatic indicates that an applicable format of values can be used; e.g. for the "Date" qualifier, this includes a proper date or date span.

Examples

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Basic Examples  (5)

Use for discovery:

Determine the distance to a galaxy:

Find the 5 nearest galaxies to Earth:

Find the equatorial coordinates of a galaxy:

Find the current sky position of a galaxy from your location:

Scope  (3)

Implicit Entity Classes  (1)

Represent the 3 brightest galaxies:

Get a list of the galaxies:

Qualifiers  (2)

Some properties accept qualifiers:

The location qualifier, which specifies the location of the observer, can accept an explicit GeoPosition, location-based Entity objects or queries that evaluate to one of these:

Dates  (1)

Date qualifiers can accept an explicit DateObject or queries that evaluate to a DateObject:

Date qualifiers can also be specified using Dated:

Neat Examples  (1)

The structure of the Local Group of galaxies is easy to visualize:

Introduced in 2019
 (12.0)