Hitomi Archive: Getting started


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, wget or download script

At the HEASARC the Hitomi archive can be accessed using the web interfaces Browse , wget or with a download script.

  • 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.

  • 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 on Feb 24 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 https://heasarc.gsfc.nasa.gov/FTP/hitomi/data/obs/1/100040010/ 
    Example 2
       wget -q -nH --cut-dirs=5 -r -l0 -c -N -np -R 'index*' -erobots=off --retr-symlinks https://heasarc.gsfc.nasa.gov/FTP/hitomi/data/obs/1/10004010/sxi/ 
  • download_wget : donwload_wget is a PERL script that uses the wget protocol, similarly to the example above, but simplify the command and allow for more flexility. You can retrive the download_wget and place it in your local machine
    Example: To download a specific sequence type: 
    > download_wget.pl https://heasarc.gsfc.nasa.gov/FTP/hitomi/data/obs/1/100001010 To get help type : > download_wget.pl help