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pdowler merged 2 commits into from
Oct 14, 2026
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start WD-ObsCore-1.2 #23

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ec1ce51
start WD-ObsCore-1.2
pdowler Sep 18, 2026
22f7ced
moved core field descriptions to table model section
pdowler Sep 25, 2026
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6 changes: 3 additions & 3 deletions Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -5,13 +5,13 @@
DOCNAME = ObsCore

# count up; you probably do not want to bother with versions <1.0
DOCVERSION = 1.1
DOCVERSION = 1.2

# Publication date, ISO format; update manually for "releases"
DOCDATE = 2017-05-09
DOCDATE = 2026-09-18

# What is it you're writing: NOTE, WD, PR, REC, PEN, or EN
DOCTYPE = REC
DOCTYPE = WD

# An e-mail address of the person doing the submission to the document
# repository (can be empty until a make upload is being made)
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177 changes: 99 additions & 78 deletions ObsCore.tex
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Expand Up @@ -285,6 +285,7 @@ \subsection{The goal of this effort}
%Fig.~\ref{fig:archdiag} shows the role this document plays within the
%IVOA architecture \citep{2021ivoa.spec.1101D}.

\iffalse % temporarily hide data model section
\section[Observation Core Components Data Model]{Observation Core Components Data Model}
\label{sec:core-components}This section highlights and describes the core components of the Observation data model,
synthetized today in the Dataset Metadata DM specification. The term ``core components'' is meant to refer to those
Expand Down Expand Up @@ -583,85 +584,12 @@ \subsubsection{File Content and Format}
analysis.

See section \ref{bkm:Ref289893457} for more details and implementation requirements.
\fi % temporarily hide data model section

\section{Implementation of ObsCore in a TAP Service}
\label{sec:obstap-impl}The ObsCore model must be implemented within Table Access Protocol (TAP) services such that all
valid queries can be executed unchanged on any service that implements the model. Additional optional or
provider-defined columns are permitted (see section \ref{bkm:Ref421295535}) so long as all mandatory columns are
provided. The protocol does not specify any specific ordering of fields in the query response so long as the mandatory
parameters are present in the output stream.
\section{ObsCore Table Model}

Here we specify an explicit mapping of the model to relational database tables; in the context of TAP this means we are
specifying the logical tables as described in the TAP\_SCHEMA (the TAP-required database schema where the tables and
columns exposed by the service are described). This does not necessarily imply that the underlying database will have
the identical structure (what is exposed through TAP could be, for example, a database view of the underlying database
tables), but in most cases the relationship between TAP\_SCHEMA description and the underlying tables is
straightforward.

%\begin{table}[h]
%\begin{center}
\begin{tabularx}{\textwidth}{|p{0.2\textwidth}|p{0.2\textwidth}|p{0.4\textwidth}|}
\hline
schema\_name & table\_name & Description\\\hline
ivoa & ivoa.ObsCore & ObsCore 1.1\\\hline
\caption{TAP\_SCHEMA.tables for implementation of the ObsCore model.}
\label{tab:3}
\end{tabularx}
%\end{center}
%\end{table}

%\begin{table}[h]
%\begin{center}
\begin{tabularx}{\textwidth}{|p{0.18\textwidth}|p{0.25\textwidth}|p{0.22\textwidth}|p{0.07\textwidth}|p{0.14\textwidth}|}
\hline
table\_name & column\_name & data type & units & Constraint\\\hline
ivoa.ObsCore & dataproduct\_type & adql:VARCHAR & & \\\hline
ivoa.ObsCore & calib\_level & adql:INTEGER & & not null\\\hline
ivoa.ObsCore & obs\_collection & adql:VARCHAR & & not null\\\hline
ivoa.ObsCore & obs\_id & adql:VARCHAR & & not null\\\hline
ivoa.ObsCore & obs\_publisher\_did & adql:VARCHAR & & not null\\\hline
ivoa.ObsCore & access\_url & adql:CLOB & & \\\hline
ivoa.ObsCore & access\_format & adql:VARCHAR & & \\\hline
ivoa.ObsCore & access\_estsize & adql:BIGINT & kbyte & \\\hline
ivoa.ObsCore & target\_name & adql:VARCHAR & & \\\hline
ivoa.ObsCore & s\_ra & adql:DOUBLE & deg & \\\hline
ivoa.ObsCore & s\_dec & adql:DOUBLE & deg & \\\hline
ivoa.ObsCore & s\_fov & adql:DOUBLE & deg & \\\hline
ivoa.ObsCore & s\_region & adql:REGION & & \\\hline
ivoa.ObsCore & s\_resolution & adql:DOUBLE & arcsec & \\\hline
ivoa.ObsCore & s\_xel1 & adql:BIGINT & & \\\hline
ivoa.ObsCore & s\_xel2 & adql:BIGINT & & \\\hline
ivoa.ObsCore & t\_min & adql:DOUBLE & d & \\\hline
ivoa.ObsCore & t\_max & adql:DOUBLE & d & \\\hline
ivoa.ObsCore & t\_exptime & adql:DOUBLE & s & \\\hline
ivoa.ObsCore & t\_resolution & adql:DOUBLE & s & \\\hline
ivoa.ObsCore & t\_xel & adql:BIGINT & & \\\hline
ivoa.ObsCore & em\_min & adql:DOUBLE & m & \\\hline
ivoa.ObsCore & em\_max & adql:DOUBLE & m & \\\hline
ivoa.ObsCore & em\_res\_power & adql:DOUBLE & & \\\hline
ivoa.ObsCore & em\_xel & adql:BIGINT & & \\\hline
ivoa.ObsCore & o\_ucd & adql:VARCHAR & & \\\hline
ivoa.ObsCore & pol\_states & adql:VARCHAR & & \\\hline
ivoa.ObsCore & pol\_xel & adql:BIGINT & & \\\hline
ivoa.ObsCore & facility\_name & adql:VARCHAR & & \\\hline
ivoa.ObsCore & instrument\_name & adql:VARCHAR & & \\\hline
\caption{List of the minimal set of data model fields to
implement for an ObsTAP service. See tables of Appendix C for the full description of the TAP\_SCHEMA.columns table.}
\label{tab:4}
\end{tabularx}
%\end{center}
%\end{table}
%\vspace{0.3cm}

Table \ref{tab:3} and Table \ref{tab:4} provide the primary information needed to describe the ObsCore model in terms of TAP\_SCHEMA tables
and columns.

The ``datatype'' column values should follow the TAP standard specification and are bound to the TAP specification
version used to implement the model. Here what is shown applies for TAP v1.0.

The content of the ``constraint'' column specified in Table \ref{tab:4} above is not part of the TAP\_SCHEMA.columns description,
but is required by the ObsCore model and specified here to make this clear to implementers. Additional standard
content for the individual columns is specified below.
ObsCore defines a simple set of core attributes to be included in a single table. This table structure can be
implemented in various services.

\subsection{Data Product Type (dataproduct\_type)}
The dataproduct\_type column contains a simple string value describing the primary nature of the data product. It
Expand Down Expand Up @@ -973,6 +901,94 @@ \subsection{Axes lengths (s\_xel1, s\_xel2, em\_xel, t\_xel, pol\_xel)}
for instance, these attributes should be set to -1. The number of elements in such lists is a different property and
should be represented in the NDCube DM which tackles sparse data sets.

\section{ObsCore Extensions}
The ObsCore table includes common metadata attributes that are applicable to a wide range of astronomical data.
Additional details that are not common enough to be included in core may be defined as extensions that support
data discovery use cases for specific kinds of data.

TODO: extension mechanism

\section{Implementation of ObsCore in a TAP Service}
TODO: TAP-specific details here

\label{sec:obstap-impl}The ObsCore model must be implemented within Table Access Protocol (TAP) services such that all
valid queries can be executed unchanged on any service that implements the model. Additional optional or
provider-defined columns are permitted (see section \ref{bkm:Ref421295535}) so long as all mandatory columns are
provided. The protocol does not specify any specific ordering of fields in the query response so long as the mandatory
parameters are present in the output stream.

Here we specify an explicit mapping of the model to relational database tables; in the context of TAP this means we are
specifying the logical tables as described in the TAP\_SCHEMA (the TAP-required database schema where the tables and
columns exposed by the service are described). This does not necessarily imply that the underlying database will have
the identical structure (what is exposed through TAP could be, for example, a database view of the underlying database
tables), but in most cases the relationship between TAP\_SCHEMA description and the underlying tables is
straightforward.

%\begin{table}[h]
%\begin{center}
\begin{tabularx}{\textwidth}{|p{0.2\textwidth}|p{0.2\textwidth}|p{0.4\textwidth}|}
\hline
schema\_name & table\_name & Description\\\hline
ivoa & ivoa.ObsCore & ObsCore 1.1\\\hline
\caption{TAP\_SCHEMA.tables for implementation of the ObsCore model.}
\label{tab:3}
\end{tabularx}
%\end{center}
%\end{table}

%\begin{table}[h]
%\begin{center}
\begin{tabularx}{\textwidth}{|p{0.18\textwidth}|p{0.25\textwidth}|p{0.22\textwidth}|p{0.07\textwidth}|p{0.14\textwidth}|}
\hline
table\_name & column\_name & data type & units & Constraint\\\hline
ivoa.ObsCore & dataproduct\_type & adql:VARCHAR & & \\\hline
ivoa.ObsCore & calib\_level & adql:INTEGER & & not null\\\hline
ivoa.ObsCore & obs\_collection & adql:VARCHAR & & not null\\\hline
ivoa.ObsCore & obs\_id & adql:VARCHAR & & not null\\\hline
ivoa.ObsCore & obs\_publisher\_did & adql:VARCHAR & & not null\\\hline
ivoa.ObsCore & access\_url & adql:CLOB & & \\\hline
ivoa.ObsCore & access\_format & adql:VARCHAR & & \\\hline
ivoa.ObsCore & access\_estsize & adql:BIGINT & kbyte & \\\hline
ivoa.ObsCore & target\_name & adql:VARCHAR & & \\\hline
ivoa.ObsCore & s\_ra & adql:DOUBLE & deg & \\\hline
ivoa.ObsCore & s\_dec & adql:DOUBLE & deg & \\\hline
ivoa.ObsCore & s\_fov & adql:DOUBLE & deg & \\\hline
ivoa.ObsCore & s\_region & adql:REGION & & \\\hline
ivoa.ObsCore & s\_resolution & adql:DOUBLE & arcsec & \\\hline
ivoa.ObsCore & s\_xel1 & adql:BIGINT & & \\\hline
ivoa.ObsCore & s\_xel2 & adql:BIGINT & & \\\hline
ivoa.ObsCore & t\_min & adql:DOUBLE & d & \\\hline
ivoa.ObsCore & t\_max & adql:DOUBLE & d & \\\hline
ivoa.ObsCore & t\_exptime & adql:DOUBLE & s & \\\hline
ivoa.ObsCore & t\_resolution & adql:DOUBLE & s & \\\hline
ivoa.ObsCore & t\_xel & adql:BIGINT & & \\\hline
ivoa.ObsCore & em\_min & adql:DOUBLE & m & \\\hline
ivoa.ObsCore & em\_max & adql:DOUBLE & m & \\\hline
ivoa.ObsCore & em\_res\_power & adql:DOUBLE & & \\\hline
ivoa.ObsCore & em\_xel & adql:BIGINT & & \\\hline
ivoa.ObsCore & o\_ucd & adql:VARCHAR & & \\\hline
ivoa.ObsCore & pol\_states & adql:VARCHAR & & \\\hline
ivoa.ObsCore & pol\_xel & adql:BIGINT & & \\\hline
ivoa.ObsCore & facility\_name & adql:VARCHAR & & \\\hline
ivoa.ObsCore & instrument\_name & adql:VARCHAR & & \\\hline
\caption{List of the minimal set of data model fields to
implement for an ObsTAP service. See tables of Appendix C for the full description of the TAP\_SCHEMA.columns table.}
\label{tab:4}
\end{tabularx}
%\end{center}
%\end{table}
%\vspace{0.3cm}

Table \ref{tab:3} and Table \ref{tab:4} provide the primary information needed to describe the ObsCore model in terms of TAP\_SCHEMA tables
and columns.

The ``datatype'' column values should follow the TAP standard specification and are bound to the TAP specification
version used to implement the model. Here what is shown applies for TAP v1.0.

The content of the ``constraint'' column specified in Table \ref{tab:4} above is not part of the TAP\_SCHEMA.columns description,
but is required by the ObsCore model and specified here to make this clear to implementers. Additional standard
content for the individual columns is specified below.

\subsection{Additional Columns}
\label{bkm:Ref421295535}\label{bkm:Ref421297012}Service providers may include additional columns in the ivoa.ObsCore
table to expose additional metadata. These columns must be described in the TAP\_SCHEMA.columns table and in the output
Expand All @@ -983,7 +999,12 @@ \subsection{Additional Columns}
as optional. ObsTAP compliant services will support all columns defined as mandatory and possibly some of the optional
ones. Queries built up using additional columns defined specifically for a given archive might not be portable.

\section{Registering an ObsTAP Service}
\section{Registering ObsCore and Extension Tables}
TODO: write this section following current practice and remove the next section.

\section{OBSOLETE: Registering an ObsTAP Service}
TODO: remove when previous section makes it obsolete

\label{sec:obstap-register}The standard identifier for this version of the ObsCore model now follows the IVOA Identifiers
v2.0 specification \citep{2016ivoa.spec.0523D} and should be ivo://ivoa.net/std/ObsCore\#core-1.1

Expand Down
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