Simple Spectral Access Protocol Version 1.1

Abstract

The Simple Spectral Access (SSA) Protocol (SSAP) defines a uniform interface to remotely discover and access one-dimensional spectra. SSA is a member of an integrated family of Status of This Document This document has been produced by the IVOA Data Access Layer Working Group. It has been reviewed by IVOA Members and other interested parties, and has been endorsed by the IVOA Executive Committee as an IVOA Recommendation. It is a stable document and may be used as reference material or cited as a normative reference from another document. IVOA's role in making the Recommendation is to draw attention to the specification and to promote its widespread deployment. This enhances the functionality and interoperability inside the Astronomical Community. This document is an update to the earlier SSA V1.04 IVOA Recommendation (February 2008). Changes from the earlier version are summarized in section 9.1. Note from the V1.0 document (this is still planned for a future version): a getCapabilities operation returning service metadata will be added which will eventually obsolete the Many of the ideas in this document originated from others involved in developing Virtual Observatory concepts and standards. In particular, the idea of using association in the query response to group similar datasets grew out of an idea originally proposed by Roy Williams. Arnold Rots originated the idea of ranking query results via a score heuristic, and helped put the coordinate systems used in SSA on firm theoretical foundation via the development of STC. Francois Bonnarel, Mireille Louys, Alberto Micol, and others contributed to the representation of astronomical metadata and in particular the Characterization data model. Laszlo Dobos contributed early implementations of the access protocol using the spectral archive at JHU.

The Table Access Protocol: Providing standard access to astronomical data

“…TAP may fail to warrant effective searches in reasonable time. In these cases, dedicated services with predefined search criteria like SSA (Doug et al, 2012), SIAv2, are able to focus on optimized criteria and discover the data of interest in more efficient way.…”

Identification of Interesting Objects in Large Spectral Surveys Using Highly Parallelized Machine Learning

“…Using the technology of Virtual Observatory, namely the combination of Table Access (Nandrekar-Heinis et al 2014) and Simple Spectra Access (Tody et al 2012) protocols we have identified less than ten objects (e.g. BT CMi or HD53416) observed both by Ondřejov 2m Perek Telescope and LAMOST.…”

Virtual observatory publishing with DaCHS

“…While this has not been missed for simple types (e.g., text vs. integer vs. float), violation of constraints imposed by controlled vocabularies has been an issue. As an instructive example, consider SSAP's creation type, which has to contain one of seven keywords, some of which are long and mixed case, like "spec-tralExtraction", as specified in Tody et al (2012). Weighing the increased complexity in the constraint language against our experience that vocabulary mismatches can quickly be diagnosed by inspecting schema validator outputs, we still decided not to add enumerations of allowed values to the constraint language.…”