The National Virtual Observatory
2006 Summer School


A Virtual Observatory Glossary

VO Data Formats

FITS
The IAU-approvided standard format for astronomical data.  FITS supports storage of multidimensional arrays and ASCII and binary tables.

VOTable
The IVOA standard format for transmitting tabular information.  VOTables are semantically similar to FITS tables, but provide a more detailed metdata framework, connectivity with VO data models and the ability to group columns within table, and tables themselves in arbitrary hierarchies.

VO Data Access Protocols

Cone Search
The cone search protocol is a very simple CGI service that returns all elements in a table deemed to be within the specified radius of the specified point.

Simple Image Access (SIA)
The SIA protocol returns images overlapping a specified region of the sky.  A VOTable with links to the image is returned.

Simple Spectral Access (SSA)
The SSA protocol returns a set of spectra in a specified region of the sky.  The basic mechanism is similar to SIA but the protocl is substantially more sophisticated and provides for recommended formats for SED's and spectra.

SkyNode
The SkyNode protocol supports sending an ADQL query to a database and returning a result.  The full SkyNode protocol also supports distributed queries that may involve more than one SkyNode, though the SkyNode protocol itself does not break up a multi-node query.  That is done by a SkyPortal.

Languages

Astronomical Data Query Language (ADQL)
A super-sub-set of  SQL which includes features to make it easier to specify cross-matches between multiple catalogs and to specify regions in the sky.

Semantics

Uniform Column/Content Descriptors (UCD)
A standardized vocabularly of short ASCII tags describing astronomical concepts.

IVOA identifiers
A way to create a unique ID for use within the entire VO.

Resource Metadata
A standardized description of all resources and services available within the VO.

Space-Time Coordinates (STC)
A complete, flexible description for describing a region or position in both space and time.

Resource Discovery

Registry
A service that allows users to search for VO resources.

Registry Access


Open Archive Interface (OAI)
A non-VO protocol used to synchronize registries

VOEvent
VO framework for publishing and receiving notifications of transient and urgent events.

Resource Access and Job Control

NESSSI
NVO Extensible, Scalable, Secure Service Infrastructure enables easier access to secured services.

PLatform for AStronomical Tool InterConnection(PLASTIC)
A service to allow collaboration between multiple processes running on the users desktop.

Common Execution Architecture (CEA)
An Astrogrid framework for provide job flows.

Request Object Management Environment (ROME)
A tool to manage the execution of a task that requires many subtasks.

Selected VO Services

Web registries (JHU, Carnivore)
Web queryable VO registries

Aladin  (in SSS)
Image visualization tool (runnable as Applet) with many catalog and VO registry querying capabilities

WESIX
Web tool to extract objects from image and register to fiducial frame using external catalogs

TOPCAT (in SSS)
Table manipulation tool with extensive matching and conversion capabilities

Mirage  (in SSS)
Table manipulation tool especially good at looking at subsamples adapted to read VOTables.

VOPlot (in SSS)
Java tool (usable as applet) to plot VOTables.

VOMegaplot (in SSS)
As above but optimized to work with very large tables.

VOStat
A simple VO and Web-enabled statistics package.

DataScope
Web tool to find all resources in a given region

SkyView (in SSS)
Web tool and  CLI application supporting geometric transformations and  mosaicking of data provided by SIA services and other image surveys.

WCSFixer (Pitt,NOAO)
Web tools to correct the astrometric headers in FITS files

OpenSkyQuery
A SkyPortal to query SkyNodes.