Introduction to RHESSI Data Analysis

Data Products
Access to Data
Analysis Modes
Combining GUI and Command Line
RHESSI Objects



RHESSI Data and Software Center Web Page

Getting Started

Data Access Guide

Installation Guide


Software Change History

Details and Links



RHESSI Data and Software Center Web Page at Goddard and Berkeley (mirror) -  The main RHESSI site for data analysis and software information.  Includes links to browse the flare catalog, look at quicklook plots, and find documentation on imaging, spectroscopy, simulations, and more.  Including:

Getting Started - The best place to start.  It has links describing where the data is, how to install and set up SSW for RHESSI, how to get started with imaging and spectroscopy, and how to stay informed about RHESSI Data Analysis.

Data Access Guide - Describes the types of RHESSI data that are available, and how to get them.

Installation Guide for RHESSI SSW

FAQ for installing and using SSW, setting up for RHESSI, using RHESSI data files and software



Data Products

Flare Catalog

Quicklook Plots

Observing Summary


Details and Links


All of the data products listed below are stored on the RHESSI data archive.  The primary archive is at Goddard, and the secondary archive is at ETH in Zurich.


Flare Catalog


Quicklook Plots


Observing Summary


Level-0 Data



Access to Data

Data Access Guide -  full description of how to access the RHESSI data from the IDL software

RHESSI software should automatically find the correct file based on the time interval you request.

FILEDB files (files that contain a list of the file name for every time interval) are distributed with SSW in the dbase directory.

Environment variables used to find the data are HSI_DATA_ARCHIVE and HSI_DATA_USER.  These should be set for each computer in the $SSW/site/setup/setup.hessi_env file.  Refer to the Installation Guide and the FAQ for more details.

If the full archive is available to you (at Goddard, ETH, and several other unofficial mirror sites), set HSI_DATA_ARCHIVE to point to it.

If not, you can:




Minimum version of IDL required to run RHESSI software is now 5.6.

Instructions for installing SSW and completing the RHESSI-specific steps required for both Unix and Windows.  RHESSI FAQ has additional information if you have trouble.

Documentation for SSW:

In the 'gen' part of SSW, there are lots of routines that are generally useful.  Before writing a function from scratch, search around in SSW to see if someone has already written what you need.

SSW is dynamic.  It's constantly changing, which is both good and bad. 



Analysis Modes

There are four ways to analyze RHESSI data. 




To run the RHESSI GUI, in an SSW IDL session type:


GUI Features:

Note:  You can achieve the same plot capabilities from the command line using the plotman method (obj -> plotman).




What's New in the RHESSI GUI




Combining GUI and Command Line



RHESSI Objects

The RHESSI software is object-oriented.  It is built from a hierarchy of connected objects - one object for each data type.

An object is a package for storing data and the operations to execute on the data.  The data includes:

The operations are called methods and are similar to subroutines or functions.  They are called with the arrow syntax ( -> ).  Think of sending the object to its method.

The main RHESSI objects are:

Below these are chains of objects containing all the intermediate data products and operations need to produce an image, lightcurve, spectrum, etc.  A single variable name is used to refer to the entire chain of objects. For example, to create an image object, type:

o = hsi_image()

o now refers to the entire chain of objects required to make an image.  When the object is instantiated (by creating it as in the line above), its control parameters are set to default values.    The user has to change only the parameters they want to be different from default.

RHESSI objects all have the following standard methods:

Normal sequence is to create an object, set non-default parameters, and generate the data product.  For example:

o = hsi_spectrum()

o -> set, obs_time_interval = ['12-feb-2004 00:20', '12-feb-2004 00:22']

o -> set, sp_time_interval=4.

spectrum = o -> getdata()

When you call getdata, the object starts at the bottom of its chain of objects and processes each object as necessary, working through to the highest level object to give you your data product.  Each object in the chain 'remembers' what it's done, so that if you change a control parameter, only the objects affected by that parameter have to reprocess.  In the HESSI GUI, there's an asterisk next to the parameters that will require more reprocessing when changed.  For instance if we now ask for a plot without changing any parameters, no reprocessing is required, just the steps necessary for making a plot:

o -> plotman

Now, say we want to change detector segment selection to just front segments 1 and 2, and change the units of the plot to flux.  We can type the following and no reprocessing will be required since the data for all detectors is always accumulated:

o -> plotman, seg_index=[[1,1,0,0,0,0,0,0,0], bytarr(9) ], sp_data_unit='flux'

These new parameter settings will now persist, since they are set into the object before creating the new plot.  We can see this by doing some gets:

IDL> print, o -> get(/seg_index_mask)

1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

IDL> print, o -> get(/sp_data_unit)


Whereas if you changed the time interval, the object at the bottom of the chain that reads the Level-0 data files must read new data and every object along the path will reprocess as necessary.


Additional Information:

Control and Info Parameters for RHESSI are listed in  the Object Parameter Table

There are additional methods available for each object

You can retrieve the intermediate objects from the main object using get(/obj,class_name='xxx') and work directly with them via set, get, getdata.



Last updated 14 October 2004 by Kim Tolbert , 301-286-3965