Table of Contents
This manual is for researchers who are not familiar with the Interactive Analysis (IA) software packages but who are familiar with the objectives of their SWS observations. This manual gives a brief introduction to using IA and provides links for more information on each command. After reading this manual you should be able to:
There are quite a few very useful Online resources concerning SWS spectra. Many of these resources may be found on the ISO SWS homepage. The SWS Instrument Data Users Manual (IDUM) is one of the very important resources that is helpful in addressing specific issues about the data.
IA3 TEST>If you have any troubles at this stage contact the system manager.
The prompt indicates that you've started the IA session. A quick word on the IA session. IA runs within the Interactive Data Language (IDL) environment. Within IDL, data which is found on disk in FITS format must be read into memory in order to be manipulated in IDL. You read the data into memory using the routines listed below. You will specify a variable name such as spd, spd0, new_spd, aar, aar10, my_aar, etc. that means something to you. IA does not care what the variable name is as long as the data tagged by the name has the correct format. Believe me, you will hear from IDL if the format is incorrect.
One final note. At times, all your variable may seem to disappear! Don't worry, they haven't. For some reason or another the routine that was running has crashed and left you within it. To get back to your data and the main level of IA3 just type retall.
There are three different data formats provided for you and one that you create:
See the SWS IDUM for further descriptions of the data formats.
Below are listed two IA commands to read data on disk into IDL structures (memory).
spd = read_fspd(<spd-filename>)
aar = read_faar(<aar-filename>)
spd, spd-filename, aar, and aar-filename, are variables that you give. You have the choice of any name to give the spd and aar variables. The spd-filename and aar-filename are the names, in quotes, of your SPDfile and AAR file respectively including the PATH to the file.
In IA you can display the SPD or the AAR. The SPD gives you a time stamp of what occurred during the observation.
We now come to what is a bit of an art. I call this section the SWS Soup. First of all, you can create an aar from an spd with all the defaults that are used in the pipeline with the following command:
It is also possible to create an AAR following a series of steps, this is the SWS Soup. The defaults of all these routines equates to the daar command.
Although this is a prefectly fine AAR, there is still more processing that can occur to clean up the spectra. In the following, I give a brief description of the commands and keywords and some idea of how I use them in my work.
The flatfielding routine applies and offset or scaling factor to the flux values per detector. It is a method of placing all detectors on the same calibration. This routine is a recognition of the imperfections in the calibration since upto this point all detectors are treated completely separately. Note: this routine will also work on an spd.
This routine comes with a number of useful keywords:
This routine removes points that are outside a level decided by the standard deviation within a calculated data bin. The bin size is either taken as a default value or input by you through a keyword.
There are a number of different methods for saving your results.
The most straightforward and easily understood method is to write fits tables of you data structures. This is the inverse of the read_fspd and read_faar commands: write_fitstable. The use is quite simple:
Note that there is only ONE command to write any IA structure in the proper fits table format.
If you want to save specific variables, and you know you will remember them in the future, you may use the IDL command save. A complete description of this command can be found in the IDL Reference Guide.
Below, I've listed a series of commands that will write a Post-Script file and send the file to a printer. Since there are many different computer systems, this 'recipe' is not at all guaranteed to work. In IDL, this recipe will produce a Post Script file, but it may be the wrong syntax to print the file. Contact your system manager if there is any problem.
$lpr -P<printer> ps-filename
Last Update: 29 December 1997 by Russell F. Shipman firstname.lastname@example.org
Revised: 29 January 1998 by Alberto Noriega-Crespo email@example.com