MAXI Archive: Getting started
The MAXI science data are organized by sequence, where a sequence corresponds to
an observation of one day in lenght. The sequences are located in the HEASARC
MAXI data archive area in the /obs directory which is divided in
1000 days interval subdirectories named MJDdd000 (where dd000 correspond to
the MJD of the start of the 1000 day).
The sequences are located in the MJDddddd, where ddddd is the MJD day.
The archive structure is therefore:
MJD55000/ MJD56000/ MJD57000/ ...
MJD56000/ MJD56001/ MJD56002/ ....
gsc_med/ gsc_low/ ssc_med/
The directories gsc_med/ gsc_low/ ssc_med/ contains up to 768 event files where each is a specific region in the sky.
Archive access : Web, wget, download script and special maxi download script
At the HEASARC the MAXI archive can be accessed using the web interfaces
Browse , the wget protocol, the download script
or a special maxi 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 maximaster
which records high-level information for each MAXI region. One day observation contains up to 768 regions
for the gsc_med/ gsc_low/ ssc_med/.
This table can be queried for position, time and 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 https protocol, if the user wants to retrieve the sequence 'MJD57002' observed
in Dec 11 2014, she/he can retrive the entire sequence (see Example 1) or data for a single instrument
(see 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/maxi/data/obs/MJD57000/MJD57002/
wget -q -nH --cut-dirs=5 -r -l0 -c -N -np -R 'index*' -erobots=off --retr-symlinks https://heasarc.gsfc.nasa.gov/FTP/maxi/data/obs/MJD57000/MJD57002/events
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/maxi/data/obs/MJD57000/MJD57002
To get help type : > download_wget.pl help
- mxdownload_wget script : The script, also distributed with HEASoft MAXI package, allows to collect data for a
given position in the sky within a time interval.
Example 1 : Download all instruments data obtained between Sep 30 and Oct 1 of 2016 at the
sky position R.A. 55.5 Dec 15.0. The chatter is set low.
mxdownload_wget.pl --coordinates 55.5,15.0 --dates 2016-09-30,2016-10-01 --instruments all --chatter 2
Example 2 : List but do not download all files relevant to the time interval
Jan 1-2 2010 at the sky position R.A. 83.633083 Dec. 22.0145
mxdownload_wget.pl -coordinates 83.633083, 22.0145 -date_from 2010-01-01 -date_to 2010-01-02 --dryrun