Difference between revisions of "Information"

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* In principle, circular polarization should be valid and meaningful, but no polarization calibration has been done (yet) so no non-ideal behavior (leakage terms, etc.) have been accounted for.
 
* In principle, circular polarization should be valid and meaningful, but no polarization calibration has been done (yet) so no non-ideal behavior (leakage terms, etc.) have been accounted for.
  
==Flare Data==
+
===Flare Data===
 
Folder [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/ Flare_20170910] contains two measurement sets at full 1-s time resolution, each with 10-min duration:
 
Folder [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/ Flare_20170910] contains two measurement sets at full 1-s time resolution, each with 10-min duration:
 
# IDB20170910154625.corrected.ms (171 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910154625.corrected.ms.tar.gz] containing the first 10 minutes of the flare (15:46:25-15:56:25 UT), calibrated but no self-calibration
 
# IDB20170910154625.corrected.ms (171 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910154625.corrected.ms.tar.gz] containing the first 10 minutes of the flare (15:46:25-15:56:25 UT), calibrated but no self-calibration
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# IDB20170910155625.corrected.ms (232 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910155625.corrected.ms.tar.gz] containing the second 10 minutes of the flare (15:56:25-16:06:25 UT)
 
# IDB20170910155625.corrected.ms (232 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910155625.corrected.ms.tar.gz] containing the second 10 minutes of the flare (15:56:25-16:06:25 UT)
 
# IDB20170910155625.corrected.ms.xx.selfcaled (77 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910155625.corrected.ms.xx.slfcaled.tar.gz] self-calibrated data for polarization XX
 
# IDB20170910155625.corrected.ms.xx.selfcaled (77 MB) [http://ovsa.njit.edu/imaging_workshop/Flare_20170910/IDB20170910155625.corrected.ms.xx.slfcaled.tar.gz] self-calibrated data for polarization XX
==All Day Quiet Sun/Active Region Data==
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===All Day Quiet Sun/Active Region Data===
 
Folder [http://ovsa.njit.edu/imaging_workshop/AR_20170710/ AR_20170710] contains 8 calibrated measurements sets at 60-s time resolution.
 
Folder [http://ovsa.njit.edu/imaging_workshop/AR_20170710/ AR_20170710] contains 8 calibrated measurements sets at 60-s time resolution.
 
# The seven UDB20170710*.corrected.ms are files for each scan separately, ranging in size from 7 - 150 MB depending on the length of the scan.
 
# The seven UDB20170710*.corrected.ms are files for each scan separately, ranging in size from 7 - 150 MB depending on the length of the scan.
 
# UDB20170710_allday.ms (268 MB) [http://ovsa.njit.edu/imaging_workshop/AR_20170710/UDB20170710_allday.ms.tar.gz] is the same data concatenated into a single file.  However, each scan has a separate source ID.
 
# UDB20170710_allday.ms (268 MB) [http://ovsa.njit.edu/imaging_workshop/AR_20170710/UDB20170710_allday.ms.tar.gz] is the same data concatenated into a single file.  However, each scan has a separate source ID.
 
The AR data are also calibrated but not self-calibrated.  In fact, we need to create a strategy for self-calibration of such data.  You can get an overview of the AR coverage on that day by looking at the plot at http://ovsa.njit.edu/flaremon/daily/2017/XSP20170710.png.  The separate scan files above are labeled with the time of the start of the scan, and each scan covers the time of continuous solar data between each calibration scan.
 
The AR data are also calibrated but not self-calibrated.  In fact, we need to create a strategy for self-calibration of such data.  You can get an overview of the AR coverage on that day by looking at the plot at http://ovsa.njit.edu/flaremon/daily/2017/XSP20170710.png.  The separate scan files above are labeled with the time of the start of the scan, and each scan covers the time of continuous solar data between each calibration scan.
 +
 +
=Possible Topics=
 +
==Calibration==
 +
The "standard", (semi-)automatic calibrations we have done so far:
 +
# Antenna-based amplitude calibration:
 +
# Reference phase calibration: antenna-based, band-averaged phases derived from "reference" observations of strong celestial radio sources every night
 +
# Daily phase calibration: antenna-based multi-band delays derived from
 +
 +
==Flare Imaging==
 +
 +
==Quiet Sun and Active Region Imaging==

Revision as of 19:43, 2 January 2018

Sample EOVSA Data

Data are here. Here are some things to consider when working with the data:

  • Antennas 1-8 and 12 have a wide sky coverage, while antennas 9-11 and 13 are the older equatorial mounts that can only cover +/- 55 degrees from the meridian. All antennas were tracking for the flare, but for portions of the all-day scan (roughly before 1600 UT or after 2400 UT) only 9 antennas will be tracking. Data for non-tracking antennas is NOT flagged, so if you try to image these periods, you'll need to manually omit ants 9-11 and 13.
  • Because of the 2.5 GHz high-pass filters, data are taken only for bands 4-34. These will be labeled spectral window (spw) 0-31 in the measurement sets. However, band 4 (spw 0) is currently not calibrated, so only the 30 spectral windows 1-31 (bands 5-34, or frequencies 3-18 GHz) are valid data. You'll need to omit spw 0 when making images.
  • In principle, circular polarization should be valid and meaningful, but no polarization calibration has been done (yet) so no non-ideal behavior (leakage terms, etc.) have been accounted for.

Flare Data

Folder Flare_20170910 contains two measurement sets at full 1-s time resolution, each with 10-min duration:

  1. IDB20170910154625.corrected.ms (171 MB) [1] containing the first 10 minutes of the flare (15:46:25-15:56:25 UT), calibrated but no self-calibration
  2. IDB20170910154625.corrected.ms.xx.selfcaled (66 MB) [2] self-calibrated data for polarization XX
  3. IDB20170910155625.corrected.ms (232 MB) [3] containing the second 10 minutes of the flare (15:56:25-16:06:25 UT)
  4. IDB20170910155625.corrected.ms.xx.selfcaled (77 MB) [4] self-calibrated data for polarization XX

All Day Quiet Sun/Active Region Data

Folder AR_20170710 contains 8 calibrated measurements sets at 60-s time resolution.

  1. The seven UDB20170710*.corrected.ms are files for each scan separately, ranging in size from 7 - 150 MB depending on the length of the scan.
  2. UDB20170710_allday.ms (268 MB) [5] is the same data concatenated into a single file. However, each scan has a separate source ID.

The AR data are also calibrated but not self-calibrated. In fact, we need to create a strategy for self-calibration of such data. You can get an overview of the AR coverage on that day by looking at the plot at http://ovsa.njit.edu/flaremon/daily/2017/XSP20170710.png. The separate scan files above are labeled with the time of the start of the scan, and each scan covers the time of continuous solar data between each calibration scan.

Possible Topics

Calibration

The "standard", (semi-)automatic calibrations we have done so far:

  1. Antenna-based amplitude calibration:
  2. Reference phase calibration: antenna-based, band-averaged phases derived from "reference" observations of strong celestial radio sources every night
  3. Daily phase calibration: antenna-based multi-band delays derived from

Flare Imaging

Quiet Sun and Active Region Imaging