Introduction to vo.ssa

Note

The network functionality in the conesearch, ssa and image modules is experimental and subject to change.

vo.ssa is a Python package to make performing Simple Spectral Access searches on popular catalogs simple.

This package uses the VO Simple Spectral Access Protocol.

Simple Usage

Some examples of simple usage follow:

from vo import ssa
tab = ssa.query_data(pos=10.2, size=65.4, band='J')

will return a vo.tree.VOTableFile object containing a list of spectral data matching the query.

This list can then be further filtered, and a single row of it passed to ssa.get_data to get the data itself:

ssa.get_data(tab.array[0])

Range-list format

Some parameters must be in range-list format as defined in Section 8.7.2 of Simple Spectral Access Protocol.

These arguments may be a string as passed verbatim to the service expecting a range-list, or a sequence. If a sequence, each item must be either:

• a numeric value
• a named value, such as, for example, ‘J’ for named spectrum (if the numeric kwarg is False)
• a 2-tuple indicating a range
• the last item my be a string indicating the frame of reference