Specview is a Java interactive 1-D spectral visualization and analysis application (it exists in an applet version as well). It is capable of:
- reading all spectral formats generated by the Hubble Space Telescope (HST) instruments in FITS format, as delivered by the MAST(http://archive.stsci.edu/).
- reading HST ACS grism spectrograms as extracted by aXe (http://www.stecf.org/software/axe/).
- reading data from a variety of instruments and file formats, such as IUE, FUSE, ISO, FORS and SDSS spectrograms, data from "generic" FITS and ASCII tables, and preview spectrograms from the MAST.
- reading data from Virtual Observatory servers published within the SSAP (Simple Spectrum Access Protocol) standard.
- reading spectral line data from VAMDC servers (http://www.vamdc.eu/).
- reading data from files in SPC Galactic format (used in the chemistry field)
- reading data from, and writing data to, documents in IVOA SED Data Model format.
- overplotting together data from the same object but taken with different instruments or spectral bands.
- overplotting line identifications taken from a variety of line lists, including user-provided lists.
- combining/splicing together data (with rescaling, trimming, resampling) from the same object but taken with different instruments or spectral bands.
- plotting multiple spectrograms in tiled mode.
- interactively overplot and renormalize spectral template and standard star spectrograms. A library of standards and templates is included in the software distribution.
- applying a Fourier low pass filter to spectrogram data.
- changing the radial velocity / redshift of a spectrogram so it can be displayed in the comoving coordinate frame.
- enabling the user to interact with the display in a number of ways:
- selecting data from multi-array files
- applying data quality filters
- changing physical units
- zooming / panning
- changing coloring schemes
- adding/editing annotations to the plots
- customizing axis labels
- browsing FITS headers and data arrays
- producing hard copies
- linear and log mappings with optional coordinate grid
- multiple display windows with synchronized cross hair cursor
- a model fitting capability enables the user to interact with multi-component spectral models in a number of ways, and fit these models to the spectral data using a choice of minimization criteria and algorithms. A Kurucz model grid is also available.
A few screen shot examples can be seen here.
Screen shot of a data fitting session This is a full screen shot so it may require that you hit the expand button, and/or maximize your browser window.
Specview was not initially conceived to be a general-purpose spectrum analysis and measurement tool. It was basically designed to enable quick, easy and simultaneous visualization of multiple 1-D spectral data sets (mainly from HST) stored in complex file formats, and to perform complex, multi-component spectral model fitting to these data. It was in a sense conceived as a partial replacement for the no longer supported Aspect spectral package. As with Aspect, operations such as spectrum arithmetic, splicing, simple and quick line profile measurement, spectral line identification, filtering / smoothing, etc, were either not supported, or supported in a very crude form in the initial releases.
Publication quality plots were also not part of the original requirements. Thus operations such as font and color selection, plot annotation, etc. were also not supported, or were supported in limited form only. Note however that Specview can save its state to files, thus complex plots can be built and saved to file for posterior recovery.
Over the years, due to continuing enhancements in both the Java support libraries, and on its performance, most of these limitations were addressed and removed, although some still remain.