Hitomi Archive: Getting started

General

The Hitomi archive is divided in two main directories science and trend data. The science data are organized by sequence, where a sequence corresponds to an observation of one day in lenght. A sequence contains data from all instruments and is identified by a 9 digit number. The /obs directory contains the science data and it is subdivided in directories named after the first digits of the sequence number under which the observations are located. The trend area instead is divided in months interval named YYYY_NN, where YYYY is the year and NN is the numeric value for the month. For each month the trend (or monitor) data are organized by type for each of the instrument. The archive structure is therefore:

Hitomi directory structure


Archive access : Web, FTP and wget

At the HEASARC the Hitomi archive can be accessed using the web interfaces Browse or via anonymous FTP or via Wget.

  • Access via Web : The archive access via the Web makes use of database table to search for the science data. The database table is hitomaster which records high-level information for each Hitomi observation. This table can be queried for position, time and several other parameters, and from the result page it is possible to select and retrieve the data files.

  • Anonymous FTP : If the observation id (sequence number) is already known, the data can be retrieved via anonymous FTP. For example, if the user wants to retrieve the sequence '100001010' observed in August 2016, she/he can either download the files individually (see Example 1) or create and download a tar file containing the entire observation (see Example 2).
  •  
    Example 1
    
            ftp heasarc.gsfc.nasa.gov 
                   (username: anonymous, password: your_e-mail_address)
            %cd hitomi/data/obs/1/100001010
            %binary
            %[prompt]
            %[m]get file_name[s]
            %quit
    
    Example 2 
    
            ftp heasarc.gsfc.nasa.gov 
                   (username: anonymous, password: your_e-mail_address)
            %cd hitomi/data/obs/1/
            % prompt
            % get 100001010.tar.gz
            %quit
    
    

  • Wget : If you have wget installed, and the observation id is already known, the data can be retrieved via 'wget'. For example using the HHTP protocal, if the user wants to retrieve the sequence '100001010' observed in August 2016, she/he can retrive the entire sequence (see Example 1) or data for a single instrument (see Example 2)
    Example 1 
     
       wget -q -nH --cut-dirs=5 -r -l0 -c -N -np -R 'index*' -erobots=off --retr-symlinks http://heasarc.gsfc.nasa.gov/FTP/hitomi/data/obs/1/100001010/ 
    
    Example 2
       wget -q -nH --cut-dirs=5 -r -l0 -c -N -np -R 'index*' -erobots=off --retr-symlinks http://heasarc.gsfc.nasa.gov/FTP/hitomi/data/obs/1/100001010/sxi/ 
    
    
    Similarly using the FTP protol the 'wget' command for the Example 1 is :
    Example 1
     
       wget --passive-ftp -q -nH --cut-dirs=5 -r -l0 -c -N -np --retr-symlinks ftp://heasarc.gsfc.nasa.gov/hitomi/data/obs/1/100001010/ 
    
    The combination of the 'wget' with the FTP protocol allows also to retrive data via a tar file. The commands for the Example 1 and 2 are:
    Example 1 
       mycom> wget --passive-ftp -q ftp://heasarc.gsfc.nasa.gov/hitomi/data/obs/1/100001010.tar 
    
    Example 2
        mycom> wget --passive-ftp -q ftp://heasarc.gsfc.nasa.gov/hitomi/data/obs/1/100001010/sxi.tar