Hinode EIS data

The Hinode spacecraft was launched on 22nd September 2006 from Japan. Data from its EUV Imaging Spectrometer (EIS) built by MSSL are now available via Astrogrid. Further details on the instrument can be found on the Hinode EIS Website.

1. Data Access via HelioScope

Hinode EIS Level 0 and Level 2 data files can be accessed via the HelioScope service.

HelioScope is launched from Astrogrid VODesktop. Follow this link for help in downloading and running up VODesktop.

After starting VODesktop, choose New All-VO HelioScope. Here you can specify a time range of interest for your data search. HelioScope will simultaneosly query several Solar and Heliospheric data archives, including the MSSL EIS archive. Follow the instructions at the HelioScope help page to download Level 0 and/or Level 2 Hinode EIS data files.

2. Data access via ADQL queries

It is also be possible to send more complex queries than the simple time range query allowed by HelioScope, to the Hinode EIS database. This is achieved by using the Query Builder to send a query on any of the EIS FITS Headers. The query needs to be formulated in ADQL (Astronomy Data Query Language), which is similar to SQL.

2.1 EIS database tables

The EIS database contains several tables. eis_level0 is the catalogue of Level 0 fits headers and eis_level2 of the Level 2 fits headers; it is also possible to send a query to the catalogue of thumbnail images (eis_thumbs) and that of EIS science studies (eis_studies).

The EIS Fits headers are described here:

2.2 Example queries

Here are examples of ADQL queries on the Level 0 fits header database:

The basic time range query, equivalent to a Helio Scope search, is:

    Select * From eis_level0 as t1 where t1.DATE_OBS > '2007-03-03T00:00:00' and t1.DATE_OBS < '2007-03-03T12:00:00'

ADQL allows one to construct more complex queries. The following one returns all entries in the EIS database within the specified time range and with values of the square of xcen + square of ycen greater than a cutoff. This is a positional query requesting observations near the solar limb.

    Select * from eis_level0 as t1 where t1.DATE_OBS > '2007-03-03T00:00:00' and 
    t1.DATE_OBS < '2007-04-03T00:00:00' and POWER( t1.XCEN , 2) + POWER( t1.YCEN , 2) > 640000.0

The following is an EIS query with condition on the exposure time to be smaller than a required value, as well as other conditions including the target of the observation and the time range (thanks to David Perez-Suarez for suggesting this query):

    Select * From eis_level0 as aa Where aa.slit_id=1 And  ( ( (aa.obt_end-aa.obt_time  ) /aa.nexp  ) /512.0  )
<20 And aa.DATE_OBS>'2007-03-15' And aa.DATE_OBS<='2007-04-20' And aa.TARGET='active region' And
aa.FMIR_SS='0'  

2.3 How to send an ADQL query to the EIS database

• Start a VOExplorer session, double click on Example Lists, then click on Solar services.
• On the list that appears on the rhs, click on Hinode EIS Level 0 and 2 (Astrogrid DSA). Now, under Actions, click on Build ADQL. This will take you to the Query Builder.
• Once the Query Builder appears, you can type in your query as a string (see red box in the screenshot below). You can select the table to query on from the drop-down box next to Table. After typing in your query, click on Validate Edit: this will check that the syntax of your query is correct and will report any errors in the Diagnostics box.
• To submit the query click on Execute.

You will see messages in the Execution pane, updating you on the progress of the task. Once the task appears as COMPLETED, a result file will appear.

To view the results launch Topcat (see Helper Applications). Then click on the result file and from the Result menu of Task Runner choose Attempt to send table to Topcat.

The image below is a plot made with Topcat showing the results of the positional query given above, for limb observations.