This is a base class to persistence. The entity attributes are generally set or updated by persistence implementations. caom2:Entity The timestamp of last modification of this entity tracks changes in metadata and supports incremental operations. The timestamp is intended to be set and/or updated when the entity is stored (e.g. in a database). caom2:Entity.lastModified This checksum of the metadata in this entity signals a change in the metadata of an instance and supports validation (e.g. to compare metadata before and after serialisation or persistence). A change in the metaChecksum can also be used to optimise operations like updating a row in the database only when the metaChecksum changed. A change in metaChecksum normally triggers a change in the lastModified timestamp. The URI must conform to the pattern {algorithm}:{hex value}, for example: \begin{verbatim}md5:4be91751541fd804e7207663a0822f56.\end{verbatim} The checksum of an entity is computed by accumulating byte representation of individual metadata values in the following order: (1) Entity.id for entities, (2) Entity.metaProducer, (3) state fields in alphabetic order (foo.a comes before foo.b) and using depth-first recursion (foo.abc.x comes before foo.def). The lastModified timestamp is not included in the metaChecksum calculation. Null values are ignored so that the addition of new fields in future versions will not change/invalidate existing checksums. Non-null values are converted to bytes as follows: \begin{itemize} \item string: UTF-8 encoded bytes \item URI: UTF-8 encoded bytes of the string representation \item VocabularyTerm: UTF-8 encoded bytes of the term (do not include the namespace) \item enumeration: the literal value converted to bytes \item float: IEEE754 single (4 bytes) \item double: IEEE754 double (8 bytes) \item boolean: convert to single byte, false=0, true=1 (1 byte) \item byte: as-is (1 byte) \item short: (2 bytes, network byte order == big endian)) \item integer: (4 bytes, network byte order == big endian) \item long: (8 bytes, network byte order == big endian) \item date: treat as a long (milliseconds since 1970-01-01 00:00:00 UTC) \end{itemize} TODO: truncatedDates=false, digestFieldNames=true, digestFieldnamesLowerCase=true TODO: external data model components: recursion or specify conversion above (interval, point, shape, multishape) caom2:Entity.metaChecksum This identifier is used to identify the tools used to produce the metadata. It also implicitly applies to child entities with null metaProducer. The form of the URI is not specified; implementations are free to use this to track metadata curation. For example, a pattern like {organisation}:{software name}-{version} is useful to support a variety of operational uses: query for metadata created by a version with a known bug or query for metadata created by an older version of the software and perform updates. caom2:Entity.metaProducer The id is a globally unique identifier (primary key) for an instance. caom2:Entity.id This is an extension of the base Entity class to support accumulated metadata checksums and accumulated lastModified timestamps for entities with child entities. caom2:CaomEntity The maximum last modification timestamp of this entity and all child entities is used to support incremental synchronization (of Observation instances). As with the instance lastModified timestamp above, this timestamp is intended to be set and/or updated when the entity is stored (e.g. in a database). caom2:CaomEntity.maxLastModified accumulated checksum of the metadata of this entity and all child entities; The URI must conform to the pattern {algorithm}:{hex value}, for example: \begin{verbatim}md5:4be91751541fd804e7207663a0822f56.\end{verbatim} The accumulated checksum of an entity is computed by accumulating the byte representation of entity checksums in the following order: (1) the metaChecksum of the current entity, (2) the accMetaChecksum of all child entities accumulated in order of the child's Entity.id. For an entity with no children, the accMetaChecksum is derived only from the metaChecksum but it is not equal to it because it is a checksum of that checksum and not a checksum of the same metadata directly. caom2:CaomEntity.accMetaChecksum an event signifiying that a previously persisted ArtifactDescription was deleted; this event can be synchronized to propagate deletions; the Entity.id of the event is equal to the Entity.id of the deleted observation and this identifier is used when performing deletions caom2:DeletedArtifactDescriptionEvent The logical identifier of the ArtifactDescription: the ArtifactDescription.uri value; this is for informational purposes only caom2:DeletedArtifactDescriptionEvent.uri an event signifiying that a previously persisted Observation was deleted; this event can be synchronized to propagate deletions; the Entity.id of the event is equal to the Entity.id of the deleted observation and this identifier is used when performing deletions caom2:DeletedObservationEvent The logical identifier of the Observation: the Observation.uri value; this is for informational purposes only caom2:DeletedObservationEvent.uri The observation is the top-level metadata structure that describes astronomical data in a data collection. caom2:Observation The name of the data collection to which this observation belongs. caom2:Observation.collection A unique logical identifier for this observation. (NEW in CAOM-2.5) TODO: limit this to one of two forms that support use cases? caom2:Observation.uri This is a short string of hexadecimal digits generated from the uri to support operational use cases (mainly: dividing workload to perform validation in parallel). The value is the first three characters of the hexadecimal representation of SHA-1 of the UTF-8 encoded bytes of the Observation.uri value. (NEW in CAOM-2.5) caom2:Observation.uriBucket This timestamp specifies the point where the metadata for the observation instance is public (can be viewed by anonymous users). A null value means the metadata is nont public. caom2:Observation.metaRelease a collection-specific sequence number for observations; re-use or reset is collection specific caom2:Observation.sequenceNumber This describes the general purpose of observation (e.g. FITS OBSTYPE keyword). Existing usage is usually OBJECT for intent = science and other values for intent = calibration. caom2:Observation.type This is an enumeration that describes the intent of the original creator of the observation. caom2:Observation.intent This is a set of groups with read permission on observation metadata for cases when the metadata is non-public (see metaRelease above). caom2:Observation.metaReadGroups A simple observation is created directly by operating a telescope and instrument (for empirical data) or by a process (for simulation data). Existing usage: the Algorithm.name values 'exposure' and 'simulation' are reserved for these cases respectively. caom2:SimpleObservation A derived observation is an observation created from one or more other observations. Examples of multiple members include: stacks of images combined to increase signal:noise ratio, mosaics combined to increase field-of-view, etc. Examples of single members: subset of comensurally observed data that is attributed/assigned to one proposal or project (with associated permissions). caom2:DerivedObservation The members are the observations grouped together by the algorithm that defines the derivation. these are the intended components of the composite product, but actual inputs are described by the provenance. Members may be simple or derived observations (arbitrary heirarchy); derived observations with one or more members may be defined such that they only include a subset of each member (they are extracted from the progenitor). Observation.uri values are used here to refer to the member observations. caom2:DerivedObservation.members A plane is a component of an observation that describes one product of the observation. caom2:Plane A unique logical identifier for this plane. Values of this identifier are used in Plane.provenance.inputs to form a reference from a product to it's progenitors. TODO: limit this to one of two forms that support use cases? (NEW in CAOM-2.5) caom2:Plane.uri This timestamp specifies the point where the metadata for the plane instance is public (can be viewed by anonymous users). A null value means the metadata is not public. The metaRelease timestamp applies to the plane metadata itself and to all artifacts with releaseType=meta. caom2:Plane.metaRelease This is a set of groups with read permission on plane metadata for cases when the metadata is non-public (see metaRelease above). caom2:Plane.metaReadGroups This timestamp specifies the point where the metadata for the plane instance is public (can be viewed by anonymous users). A null value means the metadata is not public. The dataRelease timestamp applies to all artifacts with releaseType=data. caom2:Plane.dataRelease This is a set of groups with read permission on plane data for cases when the data is non-public (see dataRelease above). caom2:Plane.dataReadGroups This describes the degree to which the data is calibrated; it is equivalent to the ObsCore calibration level field. caom2:Plane.calibrationLevel standard classification of the type of data product; describes the logical data type for the main artifacts caom2:Plane.dataProductType a physical product (typically a file) caom2:Artifact This identifier can be used to interact with an associated data management system. Existing usage: this is an internal identifier that an IVOA DataLink service can convert into a usable link to the data. TODO: There is an informal style used to make sure that these identifiers are globally unique and avoid collisions... caom2:Artifact.uri This is a short string of hexadecimal digits generated from the uri to support operational use cases (mainly: dividing workload to perform validation in parallel). The value is the first three characters of the hexadecimal representation of SHA-1 of the UTF-8 encoded bytes of the Observation.uri value. (NEW in CAOM-2.5) caom2:Artifact.uriBucket the relationship of this Artifact to the parent Plane (DataLink semantics) caom2:Artifact.productType This field indicates whether this artifact is treated as data or metadata when determining access permission. Existing usage: some collections have small previews (productType=thumbnail) that are considered metadata and are thus viewable by all users. caom2:Artifact.releaseType This field specifies the format of the resolved artifact: should be a MIME-type. caom2:Artifact.contentType This specifies the size of the stored artifact; for files, this is the file size. caom2:Artifact.contentLength this is the checksum of the artifact data; the URI must conform to the pattern {algorithm}:{hex value}, for example: \begin{verbatim} md5:4be91751541fd804e7207663a0822f56 \end{verbatim} caom2:Artifact.contentChecksum This timestamp after which content for the artifact is public. If set, this value overrides the permission implied by the releaseType and Plane release dates. Existing usage: MAST?. caom2:Artifact.contentRelease Thsi is a set of groups that are allowed to access the content of this artifact. If set, thisd overrides the permission implied by the releaseType and PLane release groups. Existing usage: unknown. caom2:Artifact.contentReadGroups This is an identifier to refer to an ArtifactDescription entity. (new in CAOM-2.5) Use case: provide standard descriptions for links in a DataLink response. caom2:Artifact.descriptionID The provides a referenceable description of artitfacts for use in DataLink responses. (NEW in CAOM-2.5) caom2:ArtifactDescription This is the logical identifier for this description used to refer to it from an artifact. Anticipated usage: this is an internal identifier that an IVOA DataLink service can use to lookup a description. TODO: There is an informal style used for Atifact.uri to make sure that these identifiers are globally unique and avoid collisions... caom2:ArtifactDescription.uri A human-readable description of an artifact. caom2:ArtifactDescription.description the algorithm that was responsible for creating the observation; for a DerivedObservation this is the algorithm that defines the intended set of members to include caom2:Algorithm common name of the algorithm; the value 'exposure' is reserved for use in SimpleObservation; TBD: publish a list of acceptable values as a machine-readable vocabulary? caom2:Algorithm.name the telescope used to acquire the data for an observation caom2:Telescope common name of the telescope; TBD: reference to a standard list of names? caom2:Telescope.name x-coordinate of the geocentric location of the telescope at the time of observation (see FITS WCS Paper III) caom2:Telescope.geoLocationX y-coordinate of the geocentric location of the telescope at the time of observation (see FITS WCS Paper III) caom2:Telescope.geoLocationY z-coordinate of the geocentric location of the telescope at the time of observation (see FITS WCS Paper III) caom2:Telescope.geoLocationZ additional keywords that describe the telescope or telscope configuration at the time of observation; keywords cannot contain the pipe (|) character - it is reserved for use in persistence systems (e.g. to store all keywords in a single column in a table) caom2:Telescope.keywords term from the (currently non-existent) IVOA Tracking vocabulary used to indicate how the telescope moves during data acquisition caom2:Telescope.trackingMode the instrument used to acquire or create the observation; this could be used for both physical instruments that acquire data or software that generates it (e.g. simulated data) caom2:Instrument common name for the instrument caom2:Instrument.name additional keywords that describe the instrument or instrument configuration at the time of observation; keywords cannot contain the pipe (|) character - it is reserved for use in persistence systems (e.g. to store all keywords in a single column in a table) caom2:Instrument.keywords collection of measured quantities that characterise the environment at the time of observation caom2:Environment typical atmospheric distortion (full-width-half-max of a point source) caom2:Environment.name fractional relative humidity [0,1] caom2:Environment.humidity angular elevation above horizon [0,90] caom2:Environment.elevation the opacity of the atmosphere [0,1] caom2:Environment.tau wavelength at which opacity was measured caom2:Environment.wavelengthTau ambient temperature at the telescope caom2:Environment.ambientTemp indicator that flux and/or color calibration is stable caom2:Environment.photometric description of the science proposal or programme that initiated the observation caom2:Proposal collection-specific identifier for the proposal caom2:Proposal.id proper name of the principal investigator caom2:Proposal.pi common name of the project this proposal belongs to; typically used for larger or long-running projects that include mutliple proposals caom2:Proposal.project title of the proposal caom2:Proposal.title additional keywords that describe the science goals of the proposal; keywords cannot contain the pipe (|) character - it is reserved for use in persistence systems (e.g. to store all keywords in a single column in a table) caom2:Proposal.keywords identifier for external resource with proposal details caom2:Proposal.reference the target of an observation caom2:Target proper name of the target caom2:Target.name resolvable target identifier; the targetID URI should be of the form {scheme}:{id} so it can be resolved (for example: naif:170100) caom2:Target.targetID type of target; typically used to figure out what the target name means and where to look for additional information about it caom2:Target.type cosmological redshift of the target caom2:Target.redshift indicates that the target is typically used as a standard (astrometric, photometric, etc) caom2:Target.standard indicates that the target is a moving object; used for solar system objects but not high proper motion stars caom2:Target.moving additional keywords that describe the target; keywords cannot contain the pipe (|) character - it is reserved for use in persistence systems (e.g. to store all keywords in a single column in a table) caom2:Target.keywords the intended position of the observation (not the position of the intended or actual target) caom2:TargetPosition the coordinate system of the coordinates caom2:TargetPosition.coordsys the equinox of the coordinates caom2:TargetPosition.equinox the observational requirements specified by the proposal caom2:Requirements flag indicating degree to which requirements were satisfied by the observation caom2:Requirements.flag description of how this data was produced caom2:Provenance collection-specific common name of the process caom2:Provenance.name identifier for external resource with proposal details caom2:Provenance.reference version of the software or process that produced the data caom2:Provenance.version name of the project that produced the data; data produced in a uniform way are typically labelled with the same project name caom2:Provenance.project common name of the entity (person, institute, etc) responsible for producing the data caom2:Provenance.producer collection-specific identifier for the processing instance that produced the data; this identifier can typcially be traced in log files or logging systems caom2:Provenance.runID timestamp describing when this process last ran and produced data caom2:Provenance.lastExecuted additional keywords that describe the processing; this may include both general descriptive words and those specific to this particular execution of the processing; keywords cannot contain the pipe (|) character - it is reserved for use in persistence systems (e.g. to store all keywords in a single column in a table) caom2:Provenance.keywords local identifier for input planes; these are the actual inputs that went into the product caom2:Provenance.inputs description of the sample (pixel) values caom2:Observable Unified Content Descriptor (UCD) that says what kind of quantity is stored caom2:Observable.ucd term describing the calibration of the observable values caom2:Observable.calibration description of the data quality caom2:DataQuality flag indicating the data quality caom2:DataQuality.flag collection of measured quantities that describe the content of the data caom2:Metrics number of sources detected per unit area caom2:Metrics.sourceNumberDensity background level caom2:Metrics.background standard deviation in the background level caom2:Metrics.backgroundStddev flux density with a signal:noise ratio of 10 caom2:Metrics.fluxDensityLimit magnitude with a signal:noise ratio of 10 caom2:Metrics.magLimit signal:noise ratio for a representative subset of samples caom2:Metrics.sampleSNR description of the position coverage and sampling of the data caom2:Position number of separate measurements (pixels) along each axis caom2:Position.dimension maximum size of spatial structure (signal) that can be recovered or seen in the data (new in CAOM-2.5) caom2:Position.maxRecoverableScale mean spatial resolution (full-width-half-max) per pixel caom2:Position.resolution range of resolution within the bounds caom2:Position.resolutionBounds median pixel size caom2:Position.sampleSize term describing the calibration of the position axis values (NEW in CAOM-2.5) caom2:Position.calibration description of the energy coverage and sampling of the data caom2:Energy simple outer bounds of energy coverage of the data (CHANGED cardinality in CAOM-2.5) caom2:Energy.bounds standard name of the energy regime(s) included in the data caom2:Energy.energyBands number of measurements (pixels) on the energy axis caom2:Energy.dimension mean spectral resolving power per pixel (relative resolution) caom2:Energy.resolvingPower range of resolving power within the bounds (relative resolution) caom2:Energy.resolvingPowerBounds mean absolute spectral resolution per pixel (new in CAOM-2.5) caom2:Energy.resolution range of absolute spectral resolution within the bounds (new in CAOM-2.5) caom2:Energy.resolutionBounds mean pixel size caom2:Energy.sampleSize telescope- and instrument-specific name for the energy band(s) included; multiple bands may be included if energies from all specified bands are included in the data (in the sense of union) caom2:Energy.bandpassName rest energy of the target energy transition (name changed in CAOM-2.5) caom2:Energy.restwav term describing the calibration of the energy axis values (new in CAOM-2.5) caom2:Energy.calibration target energy transition for this data caom2:Energy.transition description of the time coverage and sampling of the data caom2:Time time bounds that include the data (cardinality changed in CAOM-2.5) caom2:Time.bounds term describing the calibration of the time axis values caom2:Time.calibration number of discrete samples (pixels) on the time axis caom2:Time.dimension median temporal resolution per pixel caom2:Time.resolution range of resolution within the bounds caom2:Time.resolutionBounds median pixel size caom2:Time.sampleSize mean exposure time per pixel caom2:Time.exposure range of exposure within the bounds caom2:Time.exposureBounds description of polarization measurements included in the data caom2:Polarization standard polarization states included (CHANGED cardinality in CAOM-2.5) caom2:Polarization.states number of polarization states included caom2:Polarization.dimension description of a custom coordinate axis (new in CAOM-2.4) caom2:CustomAxis coordinate type code caom2:CustomAxis.ctype custom coordinate coverage (cardinality changed in CAOM-2.5) caom2:CustomAxis.bounds number of discrete samples (pixels) along custom axis caom2:CustomAxis.dimension description of a UV-plane for interferometry data (new in CAOM-2.5) caom2:Visibility range of distances in the UV plane caom2:Visibility.distance eccentricity of the distribtuion of ??? in [0,1] caom2:Visibility.distributionEccentricity fill-factor of the distribtuion of ??? in [0,1] caom2:Visibility.distributionFill This is a base class that defines a useful structure to handle terms from an external vocabulary. A specific subclass with a fixed namespace is used for values of fields within the model. odo{This could be extracted and reused in other contexts} caom2:VocabularyTerm This is the globally unique namespace for the vocabulary where definitions can be found. caom2:VocabularyTerm.namespace the word from the vocabulary caom2:VocabularyTerm.term This is a proposal for the creation of a IVOA calibration-status vocabulary. This vocabulary can be created using optional terms in the ObsCore standard to describe the calibration of each axis in the data separately. (NEW in CAOM-2.5) caom2:CalibrationStatus vocabulary term used in CAOM; this class defines constants for the CAOM Quality vocabulary (CHANGED from enumeration in CAOM-2.4) caom2:Quality vocabulary term used in CAOM; this class defines constants for the CAOM Status vocabulary (CHANGED from enumeration in CAOM-2.4) caom2:Status vocabulary term used in CAOM; this class defines constants for the CAOM TargetType vocabulary (CHANGED from enumeration in CAOM-2.4) caom2:TargetType This is a proposed vocabulary to specify the tracking mode of the telescope during the acquisition of data. (NEW in CAOM-2.5) caom2:Tracking term from the UCD1+ vocabulary (NEW from enumeration in CAOM-2.5) caom2:UCDTerm caom2:EnergyTransition caom2:EnergyTransition.species caom2:EnergyTransition.transition This enumeration describes the intent of the original creator (usually observer) in acquiring this observation. caom2:ObservationIntentType The intent of this observation was to create science data. caom2:ObservationIntentType.science The intent of this observation was to create calibration data. caom2:ObservationIntentType.calibration The intent of this observation was to create public outreach content. caom2:ObservationIntentType.outreach This enumeration describes the degree to which data has been calibrated to remove instrumental effects. odo{This is intended to be consistent with ObsCore but there is no way to convey the integer value associated with each symbol} caom2:CalibrationLevel (-1) A planned data product that does not yet exist. caom2:CalibrationLevel.PLANNED (0) Raw data in some opaque instrument-specific format. caom2:CalibrationLevel.RAW_INSTRUMENTAL (1) Raw data in a standard format. caom2:CalibrationLevel.RAW_STANDARD (2) Standard calibration steps have been applied. caom2:CalibrationLevel.CALIBRATED (3) Additional non-standard calibration steps have been applied. caom2:CalibrationLevel.PRODUCT (4) A data product output from scientific analysis. caom2:CalibrationLevel.ANALYSIS_PRODUCT Energyband provides a general set of energy regions that span the electromagnetic spectrum. The set of values and boundaries are taken from the VOResource metadata. odo{The name(s) are used to capture the literal values from VOResource, but that is not valid for X-ray and Gamma-ray} caom2:EnergyBand wavelength greater than ~10mm caom2:EnergyBand.Radio wavelength from 0.1 to 10mm caom2:EnergyBand.Millimeter wavelength from 1um to 0.1mm caom2:EnergyBand.Infrared wavelength from 300nm to 1um caom2:EnergyBand.Optical wavelength from 100 to 300nm caom2:EnergyBand.UV wavelength from 10 to 100nm caom2:EnergyBand.EUV energy from 0.12 to 120keV caom2:EnergyBand.Xray energy greater than ~120keV caom2:EnergyBand.Gammaray The rekease type is a flag indicating how an artifact is classified to determine access permissions. The name(s) of the literals are intended to capture the serialised value(s). caom2:ReleaseType access permission checks treat the protected item as data caom2:ReleaseType.data access permission checks treat the protected item as metadata caom2:ReleaseType.meta a classification of polarization (Stokes states plus other related quantities); work-around: using the name of the literal to convey the serialised value caom2:PolarizationState unpolarized caom2:PolarizationState.I Stokes linear Q caom2:PolarizationState.Q Stokes linear U caom2:PolarizationState.U Stokes circular V caom2:PolarizationState.V right-right circular caom2:PolarizationState.RR left-left circular caom2:PolarizationState.LL right-left cross-circular caom2:PolarizationState.RL left-right cross-circular caom2:PolarizationState.LR X parallel linear caom2:PolarizationState.XX Y parallel linear caom2:PolarizationState.YY XY cross-linear caom2:PolarizationState.XY YX cross-linear caom2:PolarizationState.YX linear polarized intensity: sqrt(Q^2 + U^2) caom2:PolarizationState.POLI fractional linear polarization: POLI/I caom2:PolarizationState.FPOLI linear polarization angle: 1/2 arctan(U,Q) caom2:PolarizationState.POLA elliptical polarization intensity: sqrt(Q^2 + U^2 + V^2) caom2:PolarizationState.EPOLI circular polarization intensity: |V| caom2:PolarizationState.CPOLI unpolarized intensity: I - EPOLI caom2:PolarizationState.NPOLI location on the sky caom2:types.Point caom2:types.Point.cval1 caom2:types.Point.cval2 caom2:types.Shape a circular region on the sky caom2:types.Circle caom2:types.Circle.radius multiple simple shapess describing disconnected regions as a single value caom2:types.MultiShape a simple polygon region on the sky defined a sequence of points connected by great-circle segments caom2:types.Polygon an interval that can appear in a composition caom2:types.IntervalM caom2:types.IntervalM.lower caom2:types.IntervalM.upper dimension (number of pixels) for a two-dimensional axis caom2:types.Dimension2D caom2:types.Dimension2D.naxis1 caom2:types.Dimension2D.naxis2 a set of numeric values defined by a lower and upper bound (bounds included: [a,b]) caom2:types.Interval caom2:types.Interval.lower caom2:types.Interval.upper