This page (revision-27) was last changed on 03-Aug-2023 16:53 by Peter Young

This page was created on 02-Apr-2013 16:51 by Peter Young

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Version Date Modified Size Author Changes ... Change note
27 03-Aug-2023 16:53 5 KB Peter Young to previous
26 18-Apr-2021 18:50 5 KB RichardAdacy to previous | to last CPA
25 21-Nov-2016 13:13 5 KB RichardAdacy to previous | to last CPA
24 07-Oct-2016 17:32 5 KB Peter Young to previous | to last Added section about downloading the cutout data
23 23-Mar-2016 18:53 5 KB Peter Young to previous | to last
22 23-Mar-2016 16:16 5 KB Peter Young to previous | to last
21 23-Mar-2016 16:15 5 KB Peter Young to previous | to last

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At line 1 changed one line
!!!Procedure for obtaining SDO cutouts for an EIS data-set
[{ALLOW edit EISMainUsers}]
[{ALLOW view Anonymous}]
!!!Procedure for obtaining SDO cutouts from the JSOC service
At line 3 changed one line
SDO cutouts (both AIA and HMI) can be obtained very quickly through the JSOC. In this article I illustrate how cutouts corresponding to a specific EIS raster can be obtained.
SDO cutouts (both AIA and HMI) can be obtained very quickly through the JSOC. In this article I illustrate how cutouts corresponding to a specific EIS raster can be obtained. Note that the method is generally useful and does not apply specifically to EIS: all you need is a field-of-view size and a pointing location.
At line 14 changed one line
!!Get AIA 193 cutouts
!!Request AIA 193 cutouts
At line 16 changed one line
Go the [JSOC exportdata webpage|http://jsoc.stanford.edu/ajax/exportdata.html]. In the 'RecordSet' box, type:
Go to the [JSOC exportdata webpage|http://jsoc.stanford.edu/ajax/exportdata.html]. In the 'RecordSet' box, type:
At line 18 changed one line
{{{aia.lev1_euv_12s[2011.04.15_02:30/62m@1m][193]}}}
{{{
aia.lev1_euv_12s[2011.04.15_02:30/62m@1m][193]
}}}
At line 24 changed one line
Within the processing options, select 'im-patch - Extract sub-frame'. A new box appears with various input widgets, some of which will be automatically filled in. For the others, type:
Within the processing options, select 'im-patch - Extract sub-frame'. A new box appears with various input widgets, some of which will be automatically filled in.
At line 30 added 4 lines
Make sure 'Tracking' is ticked, and also tick the 'Register' option.
For the other fields, type:
At line 34 changed one line
For 'Protocol' leave it as 'FITS'. I suggest using '**NONE**' for compression as the cutout files generally don't take up much space. Type in your name and e-mail, and then click on 'Submit Export Request'. After a couple of minutes wait, click on 'Submit status request' and you should see a link to a tar file containing your data (it may be longer for large data-sets).
For 'Protocol' leave it as 'FITS'. Type in your name and e-mail, and then click on 'Submit Export Request'. ''If you're doing this for the first time, then you will have to register.'' After a couple of minutes wait, click on 'Submit status request' and you should see a link to a tar file containing your data (it may take longer for large data-sets).
At line 36 changed one line
!!Get HMI cutouts
Note that cutouts will be rice-compressed images (there used to be an option to download uncompressed images, but this has been removed). See below for how to read compressed images quickly.
At line 46 added 4 lines
Users should be aware that the AIA de-spiking routine (which is automatically applied to all files) can remove real data, which particularly affects small-scale, dynamic phenomena. The spikes can be recovered, however, so please check the page [re-spiking AIA images|AIARespike].
!!Request HMI cutouts
At line 61 added 38 lines
!!Downloading cutout images from IDL
After you have submitted your cutout request to the JSOC you will receive a request_id of the form 'JSOC_20161007_486'. You can check the status of your request from IDL by doing:
{{{
IDL> sdo_jsoc_check_status, request_id
}}}
which will check to see if the tar file is available for downloading. If it is, then you should see a message like:
{{{
The data are available at the webpage:
http://jsoc.stanford.edu/SUM9/D862749672/S00000
}}}
You can download and unpack the tar file to your current directory by doing:
{{{
IDL> sdo_jsoc_check_status, request_id, /download
}}}
Note that the tar file is automatically removed after unpacking.
!!Reading cutout images
A cutout image can be read with:
{{{
IDL> read_sdo, file, index, data, /use_shared_lib
}}}
The /use_shared_lib keyword is highly recommended as it greatly increases the speed at which rice-compressed images are read. It may not work on all computers though (Windows?).
!!Further information
Shea Hess Webber and Peter Young have written a [document|https://pyoung.org/gsfc/JSOC%20Export%20Process.pdf] giving more information about using the JSOC service.
At line 55 changed one line
This performs sub-pixel interpolations so that when you make a movie from the cutouts you do not see the occasional pixel jumps that otherwise would be seen.
This performs sub-pixel interpolations so that when you make a movie from the cutouts you do not see the occasional pixel jumps that otherwise would be seen. This isn't recommended if you plan to re-spike your cutouts.
At line 66 changed 2 lines
''Why not download Rice-compressed files?''\\
When read_sdo reads these files there's a small delay as each file gets uncompressed. This can be irritating if you're reading a large number of files in one go. Reading the uncompressed files is much quicker.
''I want to respike my cutouts. Can I get spike cutouts?''\\
Please check the page [re-spiking AIA images|AIARespike].
At line 119 added 10 lines
''What about HARPs? How do I extract information for these?''\\
A HARP is a HMI Active Region Patch, i.e., a cutout of HMI data that has been processed to yield, e.g., the vector magnetic field. See the separate page on [Extracting HARP data from the JSOC|JsocHarp].
''Can I get header information from JSOC without downloading data?''\\
Putting the following URL into your browser will give a text page with the specified keywords (T_OBS, WAVELNTH, EXPTIME and NSPIKES) given as columns.
{{{
http://jsoc.stanford.edu/cgi-bin/ajax/show_info?ds=aia.lev1_euv_12s[2011.04.15_02:30/62m@1m][193]&key=T_OBS,WAVELNTH,EXPTIME,NSPIKES
}}}
This page (revision-27) was last changed on 03-Aug-2023 16:53 by Peter YoungTop