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

Only authorized users are allowed to rename pages.

Only authorized users are allowed to delete pages.

Page revision history

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

Page References

Incoming links Outgoing links
AIAEIS
AIAEIS

Version management

Difference between version and

At line 1 changed one line
!!!Making use of AIA data for EIS analysis
!!!Procedure for obtaining SDO cutouts for an EIS data-set
At line 3 changed one line
(This is work in progress...)
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.
At line 5 changed one line
!!Obtaining AIA cutout images
I consider an EIS active region observation that began at 02:30 UT on 15-Apr-2011. The raster took 62 mins to complete. We would like AIA 193 cutouts at 1 min cadence for the period 02:30 to 03:32, and HMI magnetograms at 45s cadence for the same period.
At line 7 changed one line
The request for AIA cutout images can be made directly from IDL as seen from the example below:
!!Get EIS pointing and FOV size
At line 9 changed one line
IDL> ssw_cutout_service,'8-feb-2011 18:38','8-feb-2011 19:50',cgiquery,queryout,ref_helio='S30E36',ref_time='8-feb-2011 18:38',fovx=100,fovy=100,wave='193',email=email_address,max_frames=73
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).
At line 11 changed one line
This requests 1 min cadence 193 A images for the time period 18:38-19:50 on 8-Feb-2011. The FOV is 100" x 100" and the center of the FOV is given by ref_helio in longitude-latitude coordinates. The reference time at which the pointing coordinates are specified is given by ref_time. It's important to give an e-mail address so that you receive notification when the cutouts are ready.
!!Get AIA 193 cutouts
At line 13 changed one line
If your coordinates are in heliocentric units, then you can convert them to longitude-latitude by
Go the [JSOC exportdata webpage|http://jsoc.stanford.edu/ajax/exportdata.html]. In the 'RecordSet' box, type:
At line 15 changed one line
IDL> lonlat=xy2lonlat((x,y),ref_time)
{{{aia.lev1_euv_12s[2011.04.15_02:30/62m@1m][193]}}}
At line 17 added one line
Click on the 'Recount' button and make sure a non-zero number of Records are found.
At line 19 added 47 lines
For 'Method', choose 'url-tar' from the drop down list. You will see a new option called 'Processing' that appears. Tick the box.
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:
LocUnits: 'arcsec from center'\\
T_Ref: '2011-04-15T03:01:02Z' (choose time from middle of raster)\\
X: 199\\
Y: 305\\
BoxUnits: pixels\\
Width: 300 (some contingency has been factored in here)\\
Height: 400 (some contingency has been factored in here)
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).
!!Get HMI cutouts
Repeat the above procedure, except that in the RecordSet box you should do:
{{{
hmi.M_45s[2011.04.15_02:30/62m@45s]
}}}
For the field of view, you need to account for the difference in plate scale between AIA and HMI, so multiply by 1.2:
Width: 360\\
Height: 480
!!Comments
''Why use pixels instead of arcsec for the FOV size?''\\
I found erratic results when using arcsec - the HMI FOV would end up with a different size to AIA.
''Why use the register option?''\\
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.
''What if I want multiple AIA filters?''\\
Instead of giving '[193]' in the RecordSet box, give e.g. '[171,304,335]'.
''How do I get AIA UV images?''\\
For these you need to give 'aia.lev1_uv_24s' in the RecordSet box.
''How do I get HMI 45s intensitygrams, or HMI 720s magnetograms?''\\
In the RecordSet box, use 'hmi.Ic_45s' and 'hmi.M_720s'.
''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.
This page (revision-27) was last changed on 03-Aug-2023 16:53 by Peter YoungTop