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 9 added 3 lines
Note that Lockheed also provide a cutout service, but this is much slower than the JSOC and does not return HMI data.
At line 9 changed one line
The wiki page ... explains how to obtain the center and FOV of an EIS raster, so you can follow the instructions there. You should get values of (xcen,ycen)=(199,305), and (fovx,fovy)=(120,160).
The wiki page [Obtaining pointing information from EIS data|EISPointing] explains how to obtain the center and FOV of an EIS raster, so you can follow the instructions there. You should get values of (xcen,ycen)=(199,305), and (fovx,fovy)=(120,160).
At line 11 changed one line
!!Get AIA 193 cutouts
!!Request AIA 193 cutouts
At line 13 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 15 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 21 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 31 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 not 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 33 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 52 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 55 changed one line
Instead of giving '[193]' in the RecordSet box, give e.g. '[171,304,335]'.
Instead of giving {{{[193]}}} in the RecordSet box, give e.g. {{{[171,304,335]}}}.
At line 63 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