Data Centre for Astrophysics
Astronomy Department of the University of Geneva
Astro ROOT

NGC 206 South West H-alpha
There is an example for most of the highlights described below at the Tutorials web page.
Access of FITS files All cfitsio functions are available in the extended root interpreter called astroroot. Furthermore, a set of container classes representing tables and images can be filled directly from a FITS file. They can store their data with one function call in FITS tables and FITS images.
FITS table to TTree conversoin Once a FITS table is read into the container class of AstroROOT, called TFTable, a TTree can be created with a member function of TFTable. The TTree will have one branch per FITS column.
FITS image to TH2x conversion Similar to the "FITS table to TTree conversion" a FITS image can be read into a container class, called TFBaseImage, and a ROOT histrogram, for example a TH2D, can be created with a method of TFBaseImage.
FITS image to TTree conversion The TFBaseImage container has not only a method to create a ROOT histogram, but also a method to create a ROOT TTree. A TTree branch is created for each dimension of the image and one for the pixel value itself. This conversion is useful to select ranges in any dimension and display the data with the TTreeViewer.
TTree to FITS table conversion One constructor of the TFTable container class fills the table with the data of a TTree. Simple branches of the TTree with just one basic variable or an array of basic variables are converted into a column of the table. Once the table is created it can be saved in a FITS file.
Astronomical image display One class of AstroROOT, called AstroImage, can display astronomical images in a TPad. With the help of the libwcs library the astronomical coordinates are displayed. Regions can be read from a region file, can be created interactively and can be saved in a file. The palette editor of the standard ROOT distribution is used to edit the color palette. A small program called astro_image can read one image from a FITS file and display it in a TCanvas.
Store astronomical data in ROOT files The container classes of AstroROOT, like the TFTable and the TFBaseImage classes, can store their data in FITS files. But these classes also can be stored directly in ROOT files. For huge tables with a lot of columns or rows and for many extensions in a file writing and reading the data in ROOT files is faster than accessing the data in FITS files.
Automatic GUI for IRAF parameter files A program, called param_gui can read an IRAF parameter file and create a GUI depending on the parameters in the parameter file. After defining the values of the parameters the associated program can be launched with a button of the GUI. With a few extra lines in the parameter file the GUI can be customized. An interface is available to open this GUI also from a compiled program.

Back to AstroRoot main page.