This release (3.3)

Starlink SPLAT is now a tool for the Virtual Observatory and has been renamed to SPLAT-VO.

In this release Starlink SPLAT-VO has been enhanced to access prototype spectral data servers (so called SSAP servers) that are being registered on the evolving virtual observatory. Using SPLAT-VO it is now possible to make queries about a region on the sky and retrieve, display and compare any spectra that are available.

Comparisons of such spectra are made possible by improvements to the Starlink AST library which can transform coordinates between various spectral systems (wavelength, frequency, energy and velocity) and between a growing number of flux systems (currently flux per unit frequency and per unit wavelength). This allows you to view various spectral from differing energy domains as a spectral energy distribution.

Other changes of note in this release:

• Spectra can now be drawn using point markers of various kinds.

• A new tool for setting the data units of spectra has been introduced.

• A new tool for obtaining statistics about a spectrum, or regions of a spectrum has been introduced.

• A new tool for transforming spectra by a redshift or by a flip and or translation has been introduced.

• The grid drawn around the spectra can now be forced to stay within the visible region of the plot window. This makes it easier to view the spectral data values and coordinates, but at a performance cost. Switch on the option Only display grid axes in visible area to see this in action.

• Postscript output can now be created in encapsulated form.

• Dual sideband data now have the coordinates of the second sideband shown along the opposing X axis of a plot. It is also possible to switch between sidebands.

• Log spacing can now be switched on from a plot (rather than by finding the plot configuration window).

• Support for data units in the line identifier and simple text formats has been added.

• Support for line identifiers to match against spectra that have data units has been added.

• SED example data can now be loaded from the main Options menu.

• The data and coordinate units of the current spectrum in a plot can now be modified to preset values quickly.

• Several new smoothing filters have been introduced - Hanning, Hamming, Welch and Barlett.

• Line identifiers are now available in the webstart version of SPLAT-VO.

• Line identifiers that fall within range of a spectrum can now be automatically loaded. Other changes allow the positioning to follow a spectrum, have the short name shown as a prefix and use horizontal orientation for the labels.

• Spectral coordinates can now have the source velocity specified as a redshift. The spectral editing tools now include relativistic velocities in their template functions.

• The motion tracker in plot windows can now report the coordinates under the pointer. The default continues to be to report the nearest coordinate and data value of the current spectrum.

• The scale factors used when drawing spectra are now related to graphics size. Previously they where related to the spectrum coordinates. This makes it easy to control the plot when displaying spectra with very different coordinates (like those downloaded from the VO), but will cause existing spectra to be re-scaled when new spectra are added to a plot.

• If should now be much faster when re-drawing many spectra that are being matching using their spectral coordinates and data units.

• The handling of errors when plotting spectra with hugely differing coordinates should be improved.

• A long standing problem with graphics corruption between plots has been fixed. (When the current spectrum was shared between plots some drawing changes effected all plots).

• A bug that meant that the postscript output of a plot was always written to the default directory has been fixed.

• Serialised spectra stacks now include full coordinate information.

• Spectra can now be transformed to and from different data units (Jy to W/m²/Hz or erg/cm²/s/Angstrom etc.).

• The system look and feel is now the platform default. Mac OS X tweaks are enabled on that platform.

• Data units are supported when editing and creating new spectra (polynomial and line fits).